Quest SARS-CoV-2 RNA, Qualitative Real-Time RT-PCR Instruction Manual
- June 6, 2024
- Quest
Table of Contents
- Intended Use
- **Summary and Explanation
- Principles of the Procedure
- Materials Required (Provided)
- Equipment and Supplies
- Self-collection Kits
- Warnings and Precautions
- **Quality Control
- Limitations
- Acknowledgment
- Performance Characteristics
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
SARS-CoV-2 RNA, Qualitative Real-Time RT-PCR (Test Code 39433)
Package Insert
For Emergency Use Only
For In-vitro Diagnostic Use – Rx Only
Intended Use
The Quest Diagnostics SARS-CoV-2 RNA, Qualitative Real-Time RT-PCR (“Quest
SARS-CoV-2 RRT-PCR”) is a real-time RT-PCR test intended for the qualitative
detection of nucleic acid from the SARS-CoV-2 in upper and lower respiratory
specimens (such as nasopharyngeal or oropharyngeal swabs, sputum, tracheal
aspirates, and bronchoalveolar lavage) collected from individuals suspected of
COVID-19 by their healthcare provider.
This test is also for use with nasal swab specimens that are self-collected at
home or in a healthcare setting by individuals using an authorized home-
collection kit when determined to be appropriate by a healthcare provider.
This test is for the qualitative detection of nucleic acid from the SARS-CoV-2
in pooled samples containing up to four of the individual upper respiratory
swab specimens (nasopharyngeal, mid-turbinate, anterior nares, or
oropharyngeal swabs) that were collected in individual vials containing
transport media from individuals suspected of COVID- 19 by their healthcare
provider. Negative results from pooled testing should not be treated as
definitive. If a patient’s clinical signs and symptoms are inconsistent with a
negative result or results are necessary for patient management, then the
patient should be considered for individual testing. Specimens included in
pools with a positive, inconclusive, or invalid result must be tested
individually prior to reporting a result. Specimens with low viral loads may
not be detected in sample pools due to the decreased sensitivity of pooled
testing.
Results are for the identification of SARS-CoV-2 RNA. The SARS-CoV-2 RNA is
generally detectable in respiratory specimens during the acute phase of
infection. Positive results are indicative of the presence of SARS-CoV-2 RNA;
clinical correlation with patient history and other diagnostic information is
necessary to determine patient infection status. Positive results do not rule
out bacterial infection or co-infection with other viruses. The agent detected
may not be the definite cause of the disease. Laboratories within the United
States and its territories are required to report all results to the
appropriate public health authorities.
Negative results do not preclude SARS-CoV-2 infection and should not be used
as the sole basis for treatment or other patient management decisions.
Negative results must be combined with clinical observations, patient history,
and epidemiological information. Specimens that are self-collected will not be
tested with an internal control to confirm that the specimen was properly
collected. Self-collected specimens from SARS-CoV-2 positive individuals may
yield negative results if the specimen was not collected properly.
Testing is limited to laboratories designated by Quest Diagnostics that are
certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA),
42 U.S.C. § 263a, and meet the requirements to perform high complexity tests.
Testing with the SARS-CoV-2 RRT-PCR test is intended for use by qualified and
trained laboratory personnel specifically instructed and trained in the
techniques of real-time RT-PCR assays. The SARS-CoV-2 RRT-PCR test is only
for use under the Food and Drug Administration’s Emergency Use Authorization.
**Summary and Explanation
**
An outbreak of pneumonia of unknown etiology in Wuhan City, Hubei Province,
China was initially reported to WHO on December 31, 2019. Chinese authorities
identified a novel coronavirus (SARS-CoV-2), which has resulted in thousands
of confirmed human infections in multiple provinces throughout China and
exported cases in several Southeast Asian countries and more recently in
Europe and the United States. Cases of severe illness and some deaths have
been reported.
The Quest Diagnostics SARS-CoV-2 RNA, Qualitative Real-Time RT-PCR aids in the
detection of SARS-CoV-2 RNA and diagnosis COVID-19 and is a real-time reverse
transcription-polymerase chain reaction test. The test’s primer and probe sets
were designed to detect RNA from individuals suspected of COVID-19 by their
healthcare provider. Testing is limited to Quest Diagnostics laboratories in
San Juan Capistrano CA, Chantilly VA, and Marlboro MA, or other laboratories
designated by Quest Laboratories that are also certified under the Clinical
Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, to perform
high complexity tests.
In sample pooling, specimens are identified from populations based on
positivity rate (for example, by county, zip code, or by client), and up to
four patient specimens are combined into a pool, and the pool is tested as
described in this package insert. If the pool is positive or inconclusive or
invalid, then each of the constituent samples is re-tested as a separate
individual specimen. If the pool is negative, then each constituent sample is
reported as negative.
Principles of the Procedure
The test is a real-time RT-PCR test intended for the qualitative detection of nucleic acid from the SARS-CoV-2 in upper respiratory specimens (for example, nasopharyngeal swabs, oropharyngeal swabs, sputum, BAL, and tracheal aspirates). The assay is composed of two principal steps: (1) extraction of RNA from patient specimens, (2) one-step reverse transcription and PCR amplification with SARS-CoV-2 specific primers, and real-time detection with 2019-nCoV specific probes. The assay targets regions of the virus nucleocapsid gene (N1 & N3) and is designed for the detection of SARS- CoV-2. Amplification and detection are accomplished using TaqMan chemistry on the ABI 7500. To ensure the absence of non-specific PCR inhibition of a sample, an internal positive amplification control (IPC) is included with each specimen. A sample can be interpreted as negative only if the analysis of the IPC indicates that amplification has occurred in the reaction tube but no signal from target reporter dye has been detected. Detection of viral RNA not only aids in the diagnosis of illness but also provides epidemiological and surveillance information.
Materials Required (Provided)
- MagnaPure Extraction
- Magna Pure 96 DNA and Viral NA – Small Volume Kit Roche Diagnostics #06 543 588 001 (3 x 192 isolations)
- Magna Pure 96 External Lysis Buffer or another comparable lysis buffer that will be validated
- Omega Extraction
- Mag-Bind Viral RNA Xpress Kit (Omega Bio-Tek, Cat. M6219-2304)
- 4X 1-Step RT-qPCR Master Mix, CG
- Exogenous NA Primer Pair
- Exogenous NA1
- TE Buffer, pH 8.0
- Quest V-C-M transport medium, Quest PBS Specimen Transport Tubes, or another comparable transport medium that will be validated
- Poly (A)
- DEPC-water
- PBS, 1X
- DTT
Reagents:
to RT-PCR Mix Primers and Probes
2019-nCoV_N1 Forward Primer
2019-nCoV_N1 Reverse Primer
2019-nCoV_N1 Probe
2019-nCoV_N3 Forward Primer
2019-nCoV_N3 Reverse Primer
2019-nCoV_N3 Probe
Reagent Preparation and Storage
Primer and Probe 10µM stocks in TE Buffer
Dilute Probes 100 µM stocks 1:10 in TE Buffer ex: 100 µL + 900 µL TE Buffer). Prepare aliquots in screw cap tubes.
Dilute Primers 200 µM stocks 1:10 in TE Buffer ex: 50 µL + 950 µL TE Buffer). Prepare aliquots in screw cap tubes.
Storage Store @ -60ºC to -90ºC
Stability 1 year from date of preparation.
Formulation sheet EFORM.129. 01480
4x RT-PCR enzyme mix 1 mL aliquots
Thaw / equilibrate 10mL bottle(s) of 4x RT-PCR enzyme mix to room temperature (protect from light). Mix bottle contents
thoroughly by inversion and gentle swirling. Transfer 1.0 mL aliquots of mix to pre-labeled sterile screw-cap tubes.
Storage Store @ -60ºC to -30ºC
Stability as specified by the manufacturer on bottle 5 mg/mL poly (A)
Dissolve 100 mg of poly (A) in 20 mL of DEPC-water in a 50 mL sterile centrifuge tube. Vortex until completely dissolved. Prepare 1 mL aliquots in screw cap tubes.
Storage Store @ -60ºC to -90ºC
Stability is 2 years from the date of preparation.
RNA Diluent P
Add 1 mL of 5 mg/mL poly (A) to 1 x 500 mL bottle of 1x PBS (new, unopened, without CA, Mg salts). Mix well. Prepare 40 mL aliquots in 50 mL sterile centrifuge tubes. The final concentration of poly (A) is 10 µg/mL.
1In the event that an RNA internal process control is temporarily unavailable, a DNA internal process control, exhibiting similar PCR performance, may be used temporarily.
DTT solution 500mM
Add 100 µL of nuclease-free water to one microtube containing DTT and mix with pipette tip. Add the entire 100µL DTT solution into 5mL of cold sterile 0.01 M PBS (pH 7.2) and mix briefly. Discard any unused reconstituted DTT
SARS-CoV-2 PCR Mix
Combine the ingredients in the amounts listed below.
Dispense in 455 µL aliquots label as NCOV PCR Mix Lot#/Prep: (preparation date. initials)
Exp. date: (1 year from preparation date)
Store at -60 to -90°C
Each aliquot is sufficient for up to 48 reactions.
Storage Store at -60 to -90°C.
Stability Expires 1 year after preparation.
See Formulation Sheet EFORM.129.001481.
Item
|
µL per reaction
| Unit of Measure for 1,000 reactions| Final Concentration per 25 µL
reaction
---|---|---|---
Sterile Nuclease Free Water| 3.75| 3.75 mL| —
2019-nCoV_N1 Forward Primer (10 µM in TE, pH 8.0)| 1.00| 1.00 mL| 0.4 µM
2019-nCoV_N1 Reverse Primer (10 µM in TE, pH 8.0)| 1.00| 1.00 mL| 0.4 µM
2019-nCoV_N1 Probe (10 µM in TE, pH 8.0)| 0.25| 0.25 mL| 0.1 µM
2019-nCoV_N3 Forward Primer (10 µM in TE, pH 8.0)| 1.00| 1.0 mL| 0.4 µM
2019-nCoV_N3 Reverse Primer (10 µM in TE, pH 8.0)| 1.00| 1.0 mL| 0.4 µM
2019-nCoV_N3 Probe (10 µM in TE, pH 8.0)| 0.25| 0.25 mL| 0.1 µM
50X Exogenous NA Primer/Probe Mix| 0.50| 0.50 mL| 1X
Total| 8.750 µ L| 8.750 mL|
Equipment and Supplies
• Applied Biosystems 7500 Real-Time PCR System (or ABI 7500 fast system run as
a standard ABI 7500)
• Roche MagNA Pure 96 System (Magna Pure extraction)
• Hamilton MagEx STAR (Omega extraction)
• Bench-top centrifuge
• Serological Pipet (Pipette Aid)
• Sterile screw cap 15 mL conical tubes
• Sterile screw cap 50 mL conical tubes
• P10, P20, P200, P1000 pipettes
• P-10, P-20, P-200, P-1000 ART Plugged Tips
• 1.5 mL or 2 mL microcentrifuge tubes
• Metal tubes
• Standard absorbent wipes
• Latex gloves and other protective equipment (see Procedure)
• Biohazard Absorbent Wipes
• 96-Well Optical Reaction Plate
• Optical Adhesive Cover
• Vortexer
• Microcentrifuge
Self-collection Kits
Quest Diagnostics Self-collection kit for COVID-19
Warnings and Precautions
-
For in vitro diagnostic use (IVD).
-
This test has not been FDA cleared or approved; the test has been authorized by FDA under an Emergency Use
Authorization (EUA) for use in laboratories designated by Quest Diagnostics that are also certified under CLIA, and meet the requirements to perform high complexity tests. -
This test has been authorized only for the detection of nucleic acid from SARS-CoV-2, not for any other viruses or pathogens
-
This test is only authorized for the duration of the declaration that circumstances exist justifying the authorization of emergency use of in vitro diagnostics for the detection and/or diagnosis of COVID-19 under Section 564(b)(1) of the Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner.
-
Follow standard precautions. All patient specimens and positive controls should be considered potentially infectious and handled accordingly.
-
Do not eat, drink, smoke, apply cosmetics or handle contact lenses in areas where reagents and human specimens are handled.
-
Handle all specimens as if infectious using safe laboratory procedures. Refer to Interim Laboratory Biosafety Guidelines for Handling and Processing Specimens Associated with 2019-nCoV https://www.cdc.gov/coronavirus/2019-nCoV/lab- biosafety-guidelines.html.
-
Specimen processing should be performed in accordance with national biological safety regulations.
-
If infection with SARS-CoV-2 is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions.
-
Performance characteristics have been determined with human upper respiratory specimens and lower respiratory tract specimens from human patients submitted for respiratory infection testing (and presumed to have signs and symptoms of disease).
Specimen Collection, Handling, and Storage
Inadequate or inappropriate specimen collection, storage, and transport are
likely to yield false test results. Training in specimen collection is highly
recommended due to the importance of specimen quality. CLSI MM13-A may be
referenced as an appropriate resource.
-
Collecting the Specimen
o Refer to Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Patients Under
Investigation (PUIs) for 2019 Novel Coronavirus (2019-nCoV) https://www.cdc.gov/coronavirus/2019– nCoV/guidelines-clinical-specimens.html
o, Follow specimen collection device manufacturer instructions for proper collection methods.
o Swab specimens should be collected using only swabs with a synthetic tip, such as nylon or Dacron®, and an aluminum or plastic shaft. Calcium alginate swabs are unacceptable and cotton swabs with wooden shafts are not recommended. Place swabs immediately into sterile tubes containing 1-3 ml of viral transport media (or PBS or saline if better alternatives are not available) -
Transporting Specimens
o Specimens must be packaged, shipped, and transported according to the current edition of the International Air Transport Association (IATA) Dangerous Goods Regulation. Follow shipping regulations for UN 3373 Biological Substance, Category B when sending potential 2019-nCoV specimens. Store specimens at 2-8°C and ship overnight on an ice pack. If a specimen is frozen at -70°C or lower, ship overnight on dry ice -
Storing Specimens
o Specimen stability after collection: 14 days at 18°C to 25°C, 14 days at 2°C to 8°C, 14 days at -10°C to -30°C, or at -70°C or lower.
o If a delay in extraction is expected, store specimens at -70°C or lower.
o Extracted nucleic acid should be stored at -70°C or lower.
Inspection of Returned Unobserved Self-Collection Specimens
Specimens that are received through the self-collection program are checked for the following criteria before entering the workflow (according to the lab’s SOP):
Are the following items present? -
Swab in the collection tube
-
Test requisition with patient name and a second identifier
-
Tube label with patient name and a second identifier
-
Collection tube that has not leaked
Is the specimen acceptable? -
The specimen is within stability criteria.
-
There is enough specimen in the collection tube.
-
The patient name and second identifier match the test requisition.
Procedure
NOTE: For all procedures involving specimens, buttoned lab coats, gloves,
and face protection are required minimum personal protective equipment. Report
all accidents to your supervisor and in accordance with the Company’s Policies
and Procedures. When performing pooling, laboratories will monitor sample
pooling in accordance with Attachment 1 – Protocol for Monitoring of Sample
Pooling Testing Strategies.
SPECIMEN TRANSFER PROCEDURE (to be performed in Extraction Room)
- Total nucleic acids (DNA and RNA) are extracted from patient specimens and assay controls using the Roche MagNA Pure 96 DNA and Viral NA Small Volume kit and the Roche MagNA Pure 96 System. Refer to PROC.129.01298- Nucleic Acid Isolation on the Magna Pure 96 Instrument for general instructions on using the MagNA Pure 96 Instrument.
- Decontaminate work area by wiping down work surface and pipettes with 10% bleach. Let soak for 1 minute. Wipe down work surface and pipettes with 70% ethanol and dry with paper towels.
- Remove one aliquot of NCOV Positive Control and NCOV Negative Control, from the freezer and let thaw at room temperature. Vortex and spin down.
- Create Magna Pure and AB7500 setup maps for the samples to be tested. 94 patient specimens can be run in a single set-up, along with 2 controls (1 Positive Control and 1 Negative control per batch). An example of a Magna Pure set-up map is provided below
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
---|---|---|---|---|---|---|---|---|---|---|---|
POS | 8 | 16 | 24 | 32 | 40 | 48 | 56 | 64 | 72 | 80 | 88 |
1 | 9 | 17 | 25 | 33 | 41 | 49 | 57 | 65 | 73 | 81 | 89 |
2 | 10 | 18 | 26 | 34 | 42 | 50 | 58 | 66 | 74 | 82 | 90 |
3 | 11 | 19 | 27 | 35 | 43 | 51 | 59 | 67 | 75 | 83 | 91 |
4 | 12 | 20 | 28 | 36 | 44 | 52 | 60 | 68 | 76 | 84 | 92 |
5 | 13 | 21 | 29 | 37 | 45 | 53 | 61 | 69 | 77 | 85 | 93 |
6 | 14 | 22 | 30 | 38 | 46 | 54 | 62 | 70 | 78 | 86 | 94 |
7 | 15 | 23 | 31 | 39 | 47 | 55 | 63 | 71 | 79 | 87 | NEG |
5. For viscous samples (sputum and bronchial wash): Performed inside BSC 2
a. Add ~ 250 µL of sample to a metal bead tube.
b. Add 350 µL PBS to each tube containing the vicious specimen.
c. Vortex tubes for about 20 seconds, repeat if needed.
d. Quick spin to deposit debris in the bottom of the tube.
Alternative method:
a. Rehydrate Thermo Scientific Pierce DTT (Dithiothreitol by adding 100 µ or
nuclease-free water to one mix containing DTT and gently mix with a pipette
tip to completely dissolve (500mM final concentration).
b. Add the entire 100 µL of freshly prepared DTT to 5 mL of cold Sterile 0.01M
PBS (pH 7.2) and mix briefly.
c. In a microcentrifuge tube, add the diluted DTT solution to an equal volume
of the specimen (e.g. 250 µL of fresh 500m DTT solution to 250 µL of the
sample). Note: Use DTT immediately. Discard any unused reconstituted DTT.
d. Incubate at room temperature with intermittent mixing until the sample is
liquified (up to 30 minutes).
e. Liquefied specimen can be used for downstream nucleic acid extraction.
6. For sample pooling, first pipette 250 µL MagNA Pure External Lysis Buffer
into the appropriate well of a Magna Pure 96 Processing Cartridge. For sample
pooling, add equal amounts of each specimen (for 4 specimens, add 50 µL each)
pipette up and down at least once after each addition (performed in BSC 2).
The decision to pool specimens should be based on the positivity rate of the
location. Pooling is permitted for NP, OP, AN, and MT swabs. For laboratories
considering pooling, please see Attachment 1 for monitoring requirements
7. For controls and all other patient specimens that are not run in a pool,
first pipette 250 µL MagNA Pure External Lysis Buffer into the appropriate
well of a Magna Pure 96 Processing Cartridge. Next, add 200 µL of controls
and patient specimens and pooled specimens, mixing by pipette at least once
after each addition (performed in BSC 2).
8. Visually check the level of samples and controls in the MagNA Pure
cartridge to ensure the sample was added to the appropriate wells.
9. Cover the MagNA Pure cartridge with an absorbent wipe and put into a clean
biohazard bag then seal it before transporting it to the Magna Pure 96
instrument.
Magna Pure 96 Nucleic Acid Extraction
1.| Refer to PROC.129.01298, Nucleic Acid Isolation on the Magna Pure 96
Instrument for general instructions on using the MagNA Pure 96 Instrument
2.| All of the following steps are performed in the Specimen Preparation Area.
3.| Perform beginning of run maintenance on the Magna Pure 96 instrument (as
described in PROC.129.01298).
4.| In the Overview tab, select Enter Order, and select “External Lysis 450 µL
”.
5| The following parameters should be loaded: MagNA Pure Kit Name: “DNA/Viral
NA SV 2.0” Protocol: “DNA BLOOD EXT LYS SV 3.1” Sample volume: 450 µL Elution
volume: 50 µL Internal Control should be “IPC”
6.| Click on the “…” button next to the IPC dropdown. Scan the barcode on the
vial of internal control. Note the fill volume (3.1mL) and the number of
samples in the batch. Set the expiration date.
7.| Set the total number of specimens and controls to match the current batch.
8.| Save the order to move to the next screen.
9.| Refer to the software for the correct volumes and placement of the liquid
reagents and disposable plastic supplies. Label the sample elution cartridge
with the batch ID.
10.| Carefully place the loaded sample cartridge on the Magna Pure 96
instrument.
11.| Confirm proper placement on the screen.
12.| Start the run by clicking Start.
13.| At the completion of the run cover the sample elution cartridge with an
adhesive plate sealer and transfer the cartridge to the PCR set up area if
processing immediately (within 30 minutes) or to frozen storage ( -70oC or
colder ) for up to one week.
14.| Tips and unused reagents may stay on the system for the next run. Cover
reagents with a foil sealing cover if not used immediately.
15.| Perform end of run maintenance on MagNAPure 96 instrument as in
PROC.129.01298.
-
1. 1. SPECIMEN TRANSFER PROCEDURE for the Omega Method using the HAMILTON STAR (to be performed in Extraction Room)
-
Total nucleic acids (DNA and RNA) are extracted from patient specimens and assay controls using the Mag-Bind Viral RNA Xpress Kit (Omega Bio-Tek) on the Hamilton MagEx STAR Autoload automated platform.
Refer to PROC.129.01744- Hamilton MagEx STAR Autoload System Use and Maintenance for general instructions on using the Hamilton STAR. -
Decontaminate work area by wiping down work surface and pipettes with 10% bleach. Let soak for 1 minute. Wipe down work surface and pipettes with 70% ethanol and dry with paper towels.
-
Remove one aliquot of NCOV Positive Control and NCOV Negative Control from the freezer and let thaw at room temperature. Vortex and spin down.
-
Create Hamilton and AB7500 setup maps for the samples to be tested. For example, 94 patient specimens can be run in a single set-up, along with 2 controls (1 Positive Control, 1 Negative, and 94 patient specimens per 96 wells).
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
---|---|---|---|---|---|---|---|---|---|---|---|
Pos | 8 | 16 | 24 | 32 | 40 | 48 | 56 | 64 | 72 | 80 | 88 |
1 | 9 | 17 | 25 | 33 | 41 | 49 | 57 | 65 | 73 | 81 | 89 |
2 | 10 | 18 | 26 | 34 | 42 | 50 | 58 | 66 | 74 | 82 | 90 |
3 | 11 | 19 | 27 | 35 | 43 | 51 | 59 | 67 | 75 | 83 | 91 |
4 | 12 | 20 | 28 | 36 | 44 | 52 | 60 | 68 | 76 | 84 | 92 |
5 | 13 | 21 | 29 | 37 | 45 | 53 | 61 | 69 | 77 | 85 | 93 |
6 | 14 | 22 | 30 | 38 | 46 | 54 | 62 | 70 | 78 | 86 | 94 |
7 | 15 | 23 | 31 | 39 | 47 | 55 | 63 | 71 | 79 | 87 | Neg |
Rotating positional control based on the load number will be used for specific
identification of the extraction plate and prevention of plate switch. Refer
to additional preventive measures on PROC.129.01038 and PROC.129.01611
5. For controls and upper respiratory patient specimens, pipette 240 uL
Hamilton Lysis Buffer followed by 200 uL of the specimen into the appropriate
well of a Hamilton deep well plate.
Note: The Hamilton is not for use with Sputum or BAL specimens.
6. Visually check the level of samples and controls in the deep well plate to
ensure the sample was added to the appropriate wells.
7. Cover the deep well plate with an absorbent wipe and put it into a clean
biohazard bag then seal it before transporting it to the Hamilton STAR.
8 Label the load name on the extraction and output to each corresponding plate
that will be loaded on the theHamiltonCheck the position of the corresponding
plates on the Hamilton deck.
|
Omega Method using the Hamilton STAR Nucleic Acid Isolation
---|---
1.| Refer to PROC.129.01744, Hamilton MagEx STAR Autoload System Use and
Maintenance for general instructions on using the Hamilton STAR.
2.| All of the following steps are performed in the Specimen Preparation Area.
3.| Perform daily maintenance on the Hamilton instrument.
4.| In the Method Launcher desktop application located on the desktop, click
on the “Omega extraction” tab, and select the number of plates to be run (up
to 4 plates). If a partial plate is run, the instrument will process as full.
5.| Refer to the software for the correct volumes and placement of the liquid
reagents and disposable plastic supplies. Label the sample elution cartridge
with the batch ID.
6.| Confirm proper placement on the screen.
7.| Start the run by clicking the green arrow located in the upper left-hand
corner of the application.
8| Double-check the accuracy of the matching load number across the extraction
and output plates.
9.| At the completion of the run cover, the sample elution plate with an
adhesive plate sealer and store at 2- 8°C until needed for PCR set-up.
10.| Tips and unused reagents may stay on the system for the next run. Cover
reagents with a foil sealing cover if not used immediately.
11.| Perform end of run maintenance on the Hamilton STAR.
Start the UV Decontamination by clicking on the “StarUVLight Software” prompt
located on the desktop. Set time for 30 minutes between each run.
The UV Decontamination must be performed once each 8-hour shift for a full 60
minutes on instruments used for the SARS-CoV-2 assay.
Setting Up Real-Time RT-PCR Reactions
1. In the Reagent Room, thaw two vials of 2019-NCOV PCR MIX for every 96
samples (94 specimens + 2 controls) in the assay run. DO NOT thaw on a heat
block or on the blowers of a biosafety hood.
2. Add 325 µl of 4X TaqPath Enzyme for every 455 µl tube of NCOV PCR MIX.
Vortex to mix and spin down.
3. KEEP 96 WELL PLATES CHILLED ON A COLD BLOCK.
4 To each well of the 96-well reaction plate, add 15 µL of 2019-NCOV PCR MIX
as needed. Transfer the 96-well Optical Reaction Plate to the PCR Setup Room.
An example of an AB7500 set-up map is provided below.
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
---|---|---|---|---|---|---|---|---|---|---|---|
Pos | 8 | 16 | 24 | 32 | 40 | 48 | 56 | 64 | 72 | 80 | 88 |
1 | 9 | 17 | 25 | 33 | 41 | 49 | 57 | 65 | 73 | 81 | 89 |
2 | 10 | 18 | 26 | 34 | 42 | 50 | 58 | 66 | 74 | 82 | 90 |
3 | 11 | 19 | 27 | 35 | 43 | 51 | 59 | 67 | 75 | 83 | 91 |
4 | 12 | 20 | 28 | 36 | 44 | 52 | 60 | 68 | 76 | 84 | 92 |
5 | 13 | 21 | 29 | 37 | 45 | 53 | 61 | 69 | 77 | 85 | 93 |
6 | 14 | 22 | 30 | 38 | 46 | 54 | 62 | 70 | 78 | 86 | 94 |
7 | 15 | 23 | 31 | 39 | 47 | 55 | 63 | 71 | 79 | 87 | Neg |
5. Add 10 µL of extracted nucleic acid (from patient specimens and controls)
to the appropriate well of the 96-well Optical Reaction Plate. Note: Make sure
to follow the Reaction Plate tray map.
6. Cover the plate with Optical Adhesive Cover.
Note: Make sure to handle the Optical Adhesive Cover on the edge only. Do
not touch the middle part of the cover.
7. Briefly centrifuge the plate to collect the reactions at the bottom of the
wells and to eliminate any air bubbles.
8. Take the covered reaction plate to the AB7500.
9 A new window will appear. Select “Absolute quantification” from the
“Assay Type” drop-down menu. Select “96- Well, Clear” from the “ Container
” drop-down menu. Select “ COVID RNA TEMPLATE” from the “Template” menu.
Click “Finish” at the bottom of the window.
The 2019-NCOV PCR MIX parameters are:
- NCOV1= FAM
- NCOV3=TAM
- IPC = Q670
10 Real-time RT-PCR parameters using the AB 7500
Stage 1: 50ºC for 15 min
Stage 2: 95ºC for 2 min
Stage 3: 95ºC for 15 sec; 55ºC for 35 sec; 50 cycles.
Sample volume is set at 25 µL
Choose Standard for correct thermal profile parameters.
11 Review the run parameters to make sure they are correct. The passive
reference should be set to “ROX.”
12 Go to the Well Inspector Menu (Double-click on 1 of the wells). Highlight
the wells not being used and click on “Omit”. Wells not in use will then
contain an X.
13 Refer to PROC.129.028 for details on how to run the plate on the AB 7500
Real-Time PCR systems.
Analyzing the Run Data, Exporting Results, and Printing
2.| Click on “Analysis”, and then click on “Analysis Settings”.
For 2019-NCOV PCR MIX
Manual Ct should be selected
Set the threshold at 0.1 for NCOV1, automatic baseline Set the threshold
at 0.01 for NCOV3, automatic baseline Set the threshold at 0.05 for IPC,
automatic baseline
3.| Click the Analyze icon () from the toolbar.
Note: Wait approximately one minute for the analysis process to be
completed.
4.| Click the Results Tab.
5.| Click the Amplification Plot tab.
6.| Choose NCOV1, NCOV3, and IPC from the Detector window.
7.| Click one well containing a specimen at a time and look at the
Amplification plot and Component plot to check for the accuracy of the result.
8.| Choose the Save option from the File menu after analyzing all the wells.
9.| To export the results to the LIS, start by highlighting the wells
containing NCOV1, NCOV3, and IPC reactions from the plate grid.
10.| From the File menu, choose Export and then Results.
11.| Select “Taqman on ‘samba ( \\lis.focusdx.priv ) ’ M in the Look
in the window.
12.| Type in the name of the plate in the File Name window (e.g.: QINF 031918
EXPORT).
Note: Make sure to export the files as a Text file (Tab-delimited file) and
include the word “EXPORT” in the file name to help distinguish exported file
from the imported file.
13.| Click the Save button.
Note: It will take approximately 15 minutes for LIS to download the results.
Do not open the exported file while it is being transferred.
14.| To print the results, choose Print from the File menu.
15.| Click Print and then click O.K.
NOTE: In the event that the test system becomes inoperable, notify
supervision or designee for further direction. Patient specimens must be
stored in a manner that maintains the integrity of the specimen.
Interpretation of Results and Reporting
Review patient results for unusual patterns, trends, or distributions in
patient results, such as an unusually high percentage of abnormal results, or
unusually high percentage of non-reactive, or indeterminate, or reactive
results. Computer-aided tools should be used when available. Refer to SOP
Quality Control Program and Molecular Infectious Diseases Department. Real-
Time Group Results Review and Release Process.
Report atypical or unexpected results or trends for this test to appropriate
supervisory personnel, prior to releasing results.
- When all controls exhibit the expected performance (Acceptance Criteria for Controls), a specimen is considered negative if all SARS-CoV-2 markers (N1, N3) cycle threshold amplification curves do not cross the threshold and the IPC amplification curve does cross the threshold line within the acceptance range.
- When all controls exhibit the expected performance, a specimen is considered Detected for SARS-CoV-2 if all markers (N1, N3) cycle threshold amplification curves cross the threshold line (<40.00 Ct). The IPC may or may not be positive as described above, but the SARS-CoV-2 result is still valid.
- When all controls exhibit the expected performance and the amplification curves for the SARS-CoV-2 markers (N1, N3) and the IPC amplification curve does not cross the threshold line within the acceptance range, possible PCR inhibition has occurred for the specimen. The specimen should be re-tested. If upon repeat testing the same situation occurs the patient result is reported as “Indeterminate due to inhibition” (TNP1146).
- When all controls exhibit the expected performance and the cycle threshold amplification curve for any one or two markers, (N1, N3) but not all two crosses the threshold line (< 40.00 Ct), the result is inconclusive for SARS-CoV-2. The sample should be rerun. If upon repeat testing the same situation occurs the patient result is reported as “Inconclusive”.
*Specimen Result Interpretation (for specimens that are not pooled)**
nCoV-N1| nCoV-N3| IPC| Interpretation| Actions
ND| ND| Within +/- 3 Ct of Negative Control| NOT DETECTED| Report to
public health authorities.
DET| DET| Not Applicable (+/-)| DETECTED| Report to public health
authorities. Store Samples at -70°C or colder to refer to the appropriate
Public Health laboratory if requested.
Only one of two SARS- nCoV-2 targets are Detected| Not Applicable (+/-)|
INCONCLUSIVE| Repeat extraction and RT-PCR. If the repeated result
remains Inconclusive, Store Samples at -70°C or colder to refer to the
appropriate Public Health laboratory if requested.
ND| ND| Undetermined or IPC out of range (>3Ct)| INVALID| Repeat
extraction and RT-PCR. If upon repeat testing the same situation occurs the
patient result is reported as “Unable to report” due to inhibition (TNP1146).
Specimen Result Interpretation for Pooled Specimens
nCoV-N1| nCoV-N3| IPC| Interpretation| Actions
ND| ND| Within +/- 3 Ct of Negative Control| NOT DETECTED| Report to
public health authorities.
DET| DET| Not Applicable (+/-)| POOLED POSITIVE – DO NOT REPORT| Repeat
each constituent specimen in the pool as a separate unpooled specimen.
Only one of two SARS- nCoV-2 targets are Detected| Not Applicable (+/-)|
POOLED INCONCLUSIVE – DO NOT REPORT| Repeat each constituent specimen in
the pool as a separate unpooled specimen.
ND| ND| Undetermined or IPC out of
range (>3Ct)| INVALID| Repeat each constituent specimen in the pool as a
separate unpooled specimen.
**Quality Control
**
Run/assay acceptability criteria:
One replicate of the positive control and one replicate of the negative
control is tested in each batch. Each control is processed as a sample,
through nucleic acid isolation and amplification/detection. Controls results
(detection cycle or Ct) are generated for the two SARS-CoV-2 targets and the
Internal Control target. Acceptable control results for the SARS- CoV-2 and
internal control are required for the run to be acceptable. An example of
acceptable control results is shown in the table below. If the Positive
Control criteria are not met, the batch is invalid and all specimens must be
repeated. If the Negative Control has a Ct value < 40.00 (and has a valid
amplification curve) for one or more of the SARS-CoV-2 targets, then this
control is invalid. This indicates possible contamination of prepared samples.
Positive patient results cannot be reported. Positive specimens on this run
must be repeated. Negative specimens may be reported given that all other
assay run criteria are met.
Examples of Acceptance Criteria for Controls (Detection cycle target ranges for controls)
Control| nCoV-N1| nCov-N3| IPC
nCoV Positive| 26.85-32.85| 26.20-32.20| 26-32
nCoV Negative| Not Detected| Not Detected| 26-32
The acceptance range for IPC is determined by negative control value in each run ± 3 Ct
Limitations
-
.All users, analysts, and any person reporting diagnostic results should be trained to perform this procedure by a competent instructor. They should demonstrate their ability to perform the test and interpret the results prior to performing the assay independently. Quest will limit the distribution of this device to only those users who have successfully completed training provided by Quest.
-
Performance of the test has only been established in upper and lower respiratory specimens (such as nasopharyngeal or oropharyngeal swabs, sputum, tracheal aspirates, and bronchoalveolar lavage/wash).
-
Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for treatment or other patient management decisions. Optimum specimen types and timing for peak viral levels during infections caused by SARS-CoV-2 have not been determined. Collection of multiple specimens (types and time points) from the same patient may be necessary to detect the virus.
-
A false-negative result may occur if a specimen is improperly collected, transported, or handled. False-negative results may also occur if amplification inhibitors are present in the specimen or if inadequate numbers of organisms are present in the specimen. Positive and negative predictive values are highly dependent on prevalence. False-negative test results are more likely when the prevalence of the disease is high. False-positive test results are more likely when prevalence is moderate to low.
-
Do not use any reagent past the expiration date.
-
If the virus mutates in the RRT-PCR target region, SARS-CoV-2 may not be detected or may be detected less predictably.
Inhibitors or other types of interference may produce a false negative result. An interference study evaluating the effect of common cold medications was not performed. -
Test performance can be affected because the epidemiology and clinical spectrum of infection caused by 2019-nCoV is not fully known. For example, clinicians and laboratories may not know the optimum types of specimens to collect, and when during the course of infection these specimens are most likely to contain levels of viral RNA that can be readily detected.
-
Quest Diagnostics did not independently evaluate Specimen Stability and Fresh-frozen Testing. Quest Diagnostics adopted standard practices recommended by the CDC EUA.
-
Quest Diagnostics did not perform an interfering substances study. The assay uses conventional well-established nucleic acid extraction methods and based on our experience with other similar assays, e.g. Influenza A and B Real- Time PCR. We do not anticipate interference from common endogenous substances. Interference studies have not been performed for this assay.
-
Quest Diagnostics did not independently evaluate in silico sensitivity or specificity. Quest Diagnostics adopted the evaluation performed by the Centers for Disease Control and Prevention.
-
Samples should only be pooled when testing demand exceeds laboratory capacity and/or when testing reagents are in short supply
-
Sample pooling has only been validated using upper respiratory swab specimens.
-
Specimens that are self-collected will not be tested with an internal control to confirm that the specimen was properly collected. Self-collected specimens from SARS-CoV-2 positive individuals may yield negative results if the specimen was not collected properly.
-
The requirement to run a sample adequacy control for all samples that were self-collected unobserved by a healthcare professional will be waived provided that the following disclosure has been acknowledged by the entity utilizing your home collection kits (or notified of the disclosure via contractual notice):
Acknowledgment
(Insert Client name) acknowledges it has received the disclosure below:
Specimens that are self-collected will not be tested with an internal control
to confirm that the specimen was properly collected. Self-collected specimens
from SARS-CoV-2 positive individuals may yield negative results if the
specimen was not collected properly.
Conditions of Authorization for the Laboratory
The Quest SARS-CoV-2 RRT-PCR test Letter of Authorization, along with the
authorized Fact Sheet for Healthcare
Providers, the authorized Fact Sheet for Patients, and other authorized
labeling are available on the FDA website:
https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19
-emergency-use-authorizations-medicaldevices/vitro-diagnostics-euas
To assist clinical laboratories running the test, the relevant Conditions of
Authorization are listed below and are required to
be met by laboratories performing the EUA test.
- Authorized laboratories using Quest SARS-CoV-2 RRT-PCR test will include with test result reports, all authorized Fact Sheets. Under exigent circumstances, other appropriate methods for disseminating these Fact Sheets may be used, which may include mass media.
- Authorized laboratories using Quest SARS-CoV-2 RRT-PCR test will perform the COVID-19 RT-PCR Test as outlined in the COVID-19 RT-PCR test Instructions for Use. Deviations from the authorized procedures, including the authorized instruments, authorized extraction methods, authorized clinical specimen types, authorized control materials, authorized other ancillary reagents, and authorized materials required to perform the COVID-19 RT-PCR Test are not permitted.
- Authorized laboratories testing authorized specimens self-collected using the Quest Diagnostics Self-collection Kit for COVID-19, or any other authorized home specimen collection kit with your product must follow any Specimens Accessioning protocols provided with the authorized self-collection kit and/or outlined in Quest Diagnostics’ “SelfCollected Sample Processing Non-Technical SOP,” when accepting specimens for testing.
- Authorized laboratories testing authorized specimens self-collected using the Quest Diagnostics Self-collection Kit for COVID-19, or any other authorized home specimen collection kit with your product, must include in the test report for specific patients whose specimen(s) were self-collected without observation the following limitation: “Specimens that are self-collected were not tested with an internal control to confirm that the specimen was properly collected. As such, unobserved self-collected specimens from SARS-CoV-2 positive individuals may yield negative results if the specimen was not collected properly”.
- Authorized laboratories that receive the Quest SARS-CoV-2 RRT-PCR test must notify the relevant public health authorities of their intent to run the test prior to initiating testing.
- Authorized laboratories using the Quest SARS-CoV-2 RRT-PCR test will have a process in place for reporting test results to healthcare providers and relevant public health authorities, as appropriate.
- Authorized laboratories will collect information on the performance of the test and report to DMD/OHT7- OIR/OPEQ/CDRH (via email: CDRH-EUA- Reporting@fda.hhs.gov) and Quest Diagnostics (via email: michael.j.wagner@questdiagnostics.com) any suspected occurrence of false positive or false negative results and significant deviations from the established performance characteristics of the test of which they become aware.
- All laboratory personnel using the test must be appropriately trained in RT-PCR techniques and use appropriate laboratory and personal protective equipment when handling this kit, and use the test in accordance with the authorized labeling.
- Quest Diagnostics and authorized laboratories using Quest SARS-CoV-2 RRT-PCRT test will ensure that any records associated with this EUA are maintained until otherwise notified by FDA. Such records will be made available to FDA for inspection upon request.
- Authorized laboratories using specimen pooling strategies when testing patient specimens with your product will include with test result reports for specific patients whose specimen(s) were the subject of pooling, a notice that pooling was used during testing and that “In very rare cases, estimated at about 1 in 1,000 (0.1%) or fewer patient specimens with low viral loads may not be detected in sample pools due to the decreased sensitivity of pooled testing.”
- Authorized laboratories implementing pooling strategies for testing patient specimens must use the “Protocol for Monitoring of Specimen Pooling Testing Strategies” to evaluate the appropriateness of continuing to use such strategies based on the recommendations in the protocol.
- Authorized laboratories will keep records of specimen pooling strategies implemented including the type of strategy, date implemented, and quantities tested, and test result data generated as part of the Protocol for Monitoring of Specimen Pooling Testing Strategies. For the first 12 months from the date of their creation, such records will be made available to FDA within 48 business hours for inspection upon request and will be made available within a reasonable time after 12 months from the date of their creation.
1Authorized Laboratories: For ease of reference, the Letter of Authorization refers to “Laboratories designated by Quest Diagnostics that are certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. § 263a, and meet the requirements to perform high complexity tests” as “authorized laboratories.”
Performance Characteristics
1) Limit of Detection
The Limit of Detection (LOD) is defined as the lowest SARS-CoV-2 RNA
concentration that is successfully detected with a probability of 95% or
greater. Sensitivity standards were prepared by serially diluting the SARS-
CoV-2 viral RNA transcript containing an 1100 nucleotide region from the N
gene in stabilizing buffer RNA Diluent P to the following concentrations:
2,580, 968, 363, 136, and 51 copies/mL. RNA was quantified by an RNA
fluorometric method (Qubit HS Assay). The LOD was evaluated by testing the
sensitivity standards over three separate runs using the SARS-CoV-2 RNA
Qualitative RT-PCR assay. In each run, 7 replicates at each concentration
level were purified using the MagNA Pure 96 and each replicate was then tested
in the ABI 7500 to yield a total of 21 replicate results at each concentration
level.
The Limit of Detection study results is shown in the table below. The
concentration of SARS-CoV-2 RNA that was successfully detected with at least a
95% detection rate was calculated as 136 copies/mL for nCoV-N1 and nCoV- N3
primer/probe sets. The LOD of the test is established at 136 copies/mL.
Table 1. Sensitivity Results for Nov RNA Qualitative RT-PCR| | |
---|---|---|---
| | | | | |
| | |
nCoV N1
|
nCoV N3
sample ID
|
nCoV copies/m L
| nCoV log copies/m L|
mean Ct
|
**detection rate***
|
mean Ct
|
**detection rate***
LOD 1| 2,580| 3.41| 30.43| 100%| 29.77| 100%
LOD 2| 968| 2.99| 31.95| 100%| 31.02| 100%
LOD 3| 363| 2.56| 33.31| 100%| 32.44| 100%
LOD 4| 136| 2.13| 34.88| 95%| 34.27| 100%
LOD 5| 51| 1.71| 35.85| 81%| 34.93| 86%
- samples w ith nCoV Ct < 40.00 cycles are considered detected (positive), nCoV Ct > 40.00 are considered not detected (negative)
2) In silico inclusivity testing.
Quest Diagnostics is using the same sequences as CDC therefore, additional in
silico studies were not performed.
CDC performed an alignment with the oligonucleotide primer and probe sequences
of the CDC 2019 nCoV Real-Time RT-PCR Diagnostic Panel with all publicly
available nucleic acid sequences for 2019-nCoV in GenBank as of February 1,
2020, to demonstrate the predicted inclusivity of the CDC 2019 nCoV Real-Time
RT-PCR Diagnostic panel. All the alignments showed 100% identity of the CDC
panel to the available 2019-nCoV sequences with the exception of one
nucleotide mismatch with the N1 forward primer in one deposited sequence.
Similarly, a single mismatch is observed in the alignment of the N3 probe. The
risk assessment of these single mismatches resulting in a significant loss in
reactivity, and false-negative result, is low due to the design of the primers
and probes with melting temperatures > 60°C and run conditions of the assay
with annealing temperature at 55°C to tolerate one to two mismatches.
3) Cross-reactivity
Organisms in the commercially available Respiratory Verification Panel were
extracted and tested with the Quest SARS-CoV-2 Real-Time RT-PCR assay to
demonstrate analytical specificity and exclusivity. The commercially available
panel is comprised of 22 individual inactivated respiratory-related pathogens
(purified, intact virus particles and bacterial cells) manufactured
specifically for use as positive controls in nucleic acid tests. There was no
cross-reactivity observed for any of the tested pathogens.
Pathogen | Strain |
---|---|
Human coronavirus 229E | 229E |
Human coronavirus OC43 | OC43 |
Human coronavirus HKU1 | HKU1 |
--- | --- |
Human coronavirus NL63 | NL63 |
Adenovirus (e.g. C1 Ad. 71) | Type 3 |
Human Metapneumovirus | 8, Peru6-2003 |
Parainfluenza virus 1-4 | Parainfluenza 1-4 |
Influenza A | A/Brisbane/10/07 |
Influenza B | B/Florida/02/06 |
Respiratory syncytial virus | A |
Rhinovirus | 1A |
Chlamydia pneumoniae | M129 |
Bordetella pertussis | A639 |
Mycoplasma pneumoniae | M129 |
4) Interfering substances study
The assay uses conventional well-established nucleic acid extraction methods
and is based on our experience with other similar assays, e.g. Influenza A and
B Real-Time PCR. We do not anticipate interference from common endogenous
substances. Interference studies have not been performed for this assay.
5) In silico cross-reactivity testing
Cross-reactivity is defined as the amplification and detection of related
viruses or other pathogens by the SARS- CoV-2 RNA Qualitative RT-PCR assay.
CDC determined that the 2019-nCoV RRT-PCR assay N1 and N3, designed for the
detection of SARS-CoV-2, showed no significant combined homologies with the
human genome, other coronaviruses (with the exception of N3 with SARS
homology), or human microflora that would predict potential false-positive
RRT-PCR results. The N3 RT-PCR is expected to cross-react with human SARS
coronavirus and bat SARS-like coronaviruses. Quest Diagnostics is using the
same sequences as CDC, therefore, additional in silico studies were determined
to be unnecessary.
6) Specimen Stability and Fresh-frozen Testing
Quest Diagnostics intends to follow the CDC’s specimen collection and
transport guidance contained in CDC EUA IFU under Specimen Collection,
Handling, and Storage and the CDC website for guidance on specimen collection
handling and storage (https://www.cdc.gov/coronavirus/2019-nCoV/lab
/guidelines-clinical-specimens.html).
7) Inter-assay Precision
Inter-assay precision is defined as the reproducibility of a sample between
assay runs and was evaluated by testing 3 replicates of 3 separate precision
standards in three separate runs using the SARS-CoV-2 RNA Qualitative RT- PCR
assay. The precision standards were aliquots of the same standards prepared as
described in the Intra-assay Precision section. Precision standard replicates
CVs ranged from 0.1% to 0.7%, with mean overall inter-assay precision equal to
0.3%. The individual precision standard replicate results were within 0.20
detection cycles of their respective mean values.
8) Intra-assay Precision
Intra-assay precision is defined as the reproducibility of a sample within an
assay run and was evaluated by testing 3 replicates of 3 separate precision
standards in a single run using the SARS-CoV-2 RNA Qualitative RT-PCR assay.
The precision standards were prepared by diluting the SARS-CoV-2 viral RNA
transcript containing an 1100 nucleotide region from the N gene in
stabilizing buffer RNA Diluent P to final concentrations of 44,000 copies/mL
(high), 13,200 copies/mL (mid), and 5,657 copies/mL (low). Aliquots of each
standard were prepared and stored frozen until the time of testing. Precision
standard replicates CVs ranged from 0.0% to 0.4%, with mean overall intra-
assay precision equal to 0.3%. The individual precision standard replicate
results were within 0.13 detection cycles of their respective mean values. The
intra-assay precision data is included in the table below.
9) Clinical Evaluation:
The clinical evaluation consisted of 30 SARS-COV-2 RNA-positives and 30 SARS-
COV-2 RNA-negatives (negatives were RNA Diluent P buffer). SARS-COV-2 RNA-
positives consisted of 24 virus-positive RNA preparations derived from
clinical specimens, with 6 randomly selected and run in duplicate for a total
of 30 positives. RNA preparations were obtained from a well-established
clinical laboratory located in the Republic of Korea (originating lab) and
consisted of 12 paired extracted patient samples from both an upper
respiratory (NP/OP swabs) and lower respiratory source (sputum). Extraction
from patient specimens was performed using the Magna Pure 96 system and MagNA
Pure 96 DNA and Viral NA Small Volume Kit. Amplification was performed using
an RT- PCR kit commercially available in the Republic of Korea to identify the
paired RRT- PCR positives. The samples were randomized, blind-labeled, and
tested using the SARS-CoV-2 RNA Qualitative RT-PCR assay. Considering the
SARS-CoV-2 RNA positive RNA extracts would degrade during the nucleic acid
extraction step of the assay only the RT-PCR amplification and detection step
was performed in this study. RT-PCR Mix 1 and RT- PCR Mix 2 were formulated
to include the RNA internal positive amplification control (RIPC) at a final
concentration that is comparable to the expected concentration in
MP96-extracted preparations. There was 100% agreement (30/30, 95% CI
88.7-100%) for the positive samples and 100% agreement for the negative
samples (30/30, 95% CI 88.7-100%).
| Comparator RT-PCR Test
---|---
Positive| Negative
Quest SARS-CoV-2 RRT-PCR Test| Positive| 30| 0
Negative| 0| 30
Positive Percent Agreement: 100% (95% CI 88.7-100%)
Negative Percent Agreement: 100% (95% CI 88.7-100%)
Overall Agreement: 100% (95% CI 93.98-100%)
10) Specificity in a Presumed Negative Population (Upper Respiratory)
Quest Diagnostics randomly selected 72 presumed-negative nasopharyngeal/throat
swabs submitted for respiratory pathogen testing in October 2019 and stored at
< -10°C. One specimen was initially indeterminant, and upon repeat testing,
RNA was not detected. SARS-CoV-2 RNA was not detected in any of the samples
tested for the specificity of 100% (72/72, 95% CI 95-100%).
11) Specificity in a Presumed Negative Population (Lower Respiratory)
Quest Diagnostics randomly selected 30 presumed-negative lower respiratory
specimens (and one upper respiratory specimen) submitted for respiratory
pathogen testing during January and early February 2020, including 22 BAL
specimens, 8 sputum specimen remnants, and one M4 swab specimen. The sputum
and M4 swab remnants were tested in duplicate and the first result was used
for the analysis. SARS-CoV-2 RNA was not detected in any of the replicates
tested. One of the sputum specimens had invalid results for the internal
control in all RT- PCR reactions (replicates were out of range by about 1
cycle). The invalid sputum sample was noted to be highly mucopurulent in both
the raw and pre-processed states, possibly causing the inhibitory result.
Excluding the one invalid result, the specificity with presumed negative lower
respiratory specimens was 100% (29/29, 95%CI 88.1- 100%).
12) Post-CLIA Validation Confirmation with a Public Health RT-PCR
After the assay’s CLIA validation was completed and the clinical laboratory
testing service was made commercially available, Quest Diagnostics sent the
first five positive specimens and the first five negative specimens that had
been submitted for clinical testing to a county public health laboratory
located in Southern California for confirmation testing with a CDC-based RT-
PCR. The public health laboratory results agreed with the Quest assay results:
100% (5/5, 95% CI 47.8-100%) agreement with the positives and 100% (5/5, 95%
CI 47.8-100%) agreement with negatives.
13) Comparison with the Prior Version of the Quest SARS-CoV-2 RRT-PCR test
(n = 460)
Quest Diagnostics selected a total of 460 de-identified specimens from its
clinical laboratory testing runs and compared the new version of the assay
containing N1 and N3 targets (“New RT-PCR”) versus the initial version of the
text containing the N1 and N2 targets (“Comparator RT-PCR”). using the same
extracted specimen. For each specimen, the N1 and N3 targets were performed
together in a well, and the N2 target was performed in a separate well. Of the
460 specimens, the results for the Comparator RT-PCR were 35 detected, 421
undetected, and four inconclusive. Of the 35 specimens that were detected in
the Comparator RT-PCR, the New RT-PCR agreed 100% (35/35, 95%CI 90.0-100%).
Of the 421 specimens that were undetected in the Comparator RT-PCR, the New
RTPCR agreed 100% (421/421, 95%CI 99.1-100%). Of the four specimens that were
inconclusive in the Comparator RT-PCR, three of the four were detected and
one was inconclusive in the New RT-PCR.
Comparison with the Prior Version of the Quest SARS-CoV-2 RRT-PCR test (n = 460)
New RT-PCR (N1+N3) | Comparator RT-PCR (N1+N2) |
---|---|
Detected | Inconclusive |
Detected | 35 |
Inconclusive | 0 |
Not Detected | 0 |
14) Unobserved Self-Collection Validation:
A usability study was conducted to confirm that patients could follow the
instructions included in the Quest self-collection kit to appropriately
collect, package, and ship a self-collected nasal specimen to a Quest
Diagnostics laboratory for testing. The study was completed in an actual home-
use environment.
After providing informed consent, participants were mailed a Quest self-
collection kit, which included the instructions for use, test requisition
form, foam nasal swab, specimen transport tube containing transport media,
biohazard bag containing desiccant, transport box, pre-printed FedEx label,
and shipping bag. The participants proceeded to collect a nasal specimen
unobserved in their home environment and then shipped the specimens back to
Quest laboratory via FedEx following the instructions on the kit. Participants
were also asked to fill out a questionnaire that assessed their ability to
understand the different steps in the instructions for use.
A total of 47 individuals were consented to participate in the study. These
participants included individuals representing varying education levels and
age ranges. Of the 47 individuals, 42 returned the kit and questionnaire
within the study window. Of these 42, 95.2% (40/42) returned a specimen that
was acceptable for testing according to pre-determining acceptance criteria.
The returned specimens were also tested with a PCR assay detecting the
internal housekeeping gene RNase P. All specimens yielded strong RNase P
signals, indicating successful sampling of human biological material.
15) Shipping Stability Study
A specimen stability study was conducted to confirm that signal degradation
at high temperatures would not occur during shipping. Contrived samples for
this study were prepared by spiking a SARS-CoV-2 remnant positive patient
sample into pooled remnant SARS-CoV-2 negative patient samples at
concentrations targeting 2X LoD and 5-10X LoD. The remnant patient samples
used for this study included upper respiratory swabs in two different
transport media: VCM and sterile saline (0.9% NaCl). For each transport media,
a total of 20 replicates at 2X LoD and 10 replicates at 5-10X LoD were tested.
This study simulated shipping conditions by cycling the samples through the following temperature excursion:
Storage Temperature| Time at Storage Temp (hours)| Total Time
(hours)
---|---|---
40°C| 8| 8
22°C| 4| 12
40°C| 2| 14
30°C| 36| 50
40°C| 6| 56
Samples were tested at each time point with the Quest SARS-CoV-2 assay. The Ct
values at each time point were compared to the Ct values at time zero. All
samples for both transport media remained positive at 56 hours after cycling
in and out of high temperatures. Additionally, Ct values remained less than 1
Ct between time 0 and 56 hours, indicating acceptable specimen stability under
simulated shipping conditions.
16) Pooling Validation/ Sensitivity for Pools with One Positive Sample and
Three Negative Samples (n = 101)
Quest Diagnostics evaluated the sensitivity of sample pooling using positive
samples collected from three different populations with the following
positivity rates: 0-3% (n=30), 3-6% (n=36) and 6-10% (n=35). The samples were
sequentially selected from de-identified specimen remnants that had been
previously tested individually using the Quest Diagnostics SARS-2-CoV RT-PCR
molecular assay. Sample pools were made by combining one positive sample and
three negative samples. Each pool was tested, and agreement with the
individual sample result was calculated. Since any pool that does not yield
negative results is re-tested individually, the positive percent agreement
includes all pools that were not negative (i.e., positive, inconclusive, and
invalid). Of the 30 pools in the 1-3% positivity rate group, 100% (30/30,
95%CI 88.7-100%) were not negative (30/30 were positive). Of the 36 pools in
the 3-6% prevalence group, 100% (36/36, 95%CI 90.4-100%) were not negative
(36/36 were positive). Of the 35 pools in the 610% prevalence group, 100%
(35/35, 95%CI 90.1-100%) were not negative (33/35 were positive, and 2/35 were
inconclusive). Overall in the study, none of the 101 positive specimens would
have been determined to be negative when tested in a pool of 4 samples (0/101,
95% CI 0.0-3.7%).
Sensitivity for Pools with One Positive Sample and Three Negative Samples (n = 101)
Positivity Rate Group| n| Results of Pooled Specimens| % Positive Percent
Agreement*
---|---|---|---
Negative| Inconclusive| Positive| Invalid
1-3%| 30| 0| 0| 30| 0| 100% (30/30)
95%CI: (88.7-100%)
3-6%| 36| 0| 0| 36| 0| 100% (36/36)
95%CI 90.4-100%
6-10%| 35| 0| 2| 33| 0| 100% (35/35)
95%CI 90.1-100%
total| 101| 0| 2| 99| 0| 100% (101/101)
95%CI 96.3-100%
- Since any pool that is not negative is re-tested as an individual sample, the % Agreement includes all pools that were not negative (i.e., positive, inconclusive and invalid).
17) Pooling Validation – Efficiency with Pooled Negative Specimens (n =
247)
Quest Diagnostics evaluated the efficiency of sample pooling using negative
samples collected from three different populations with the following
positivity rates: 1-3% (n=103), 3-6% (n=107) and 6-10% (n=37).The samples
were selected sequentially from de-identified specimen remnants that had been
previously tested individually using the Quest Diagnostics SARS-2-CoV RT-PCR
molecular assay. Each 4-sample pool contained four negative samples.
Each pool was tested and the percent of negative results for these pools was
calculated. Of the 103 4-sample pools in the 1-3% prevalence group, 99.0%
(102/103, 95%CI 94.9- 99.8%) were negative, and 1/103 was inconclusive. Of the
107 4-sample pools in the 3-6% prevalence group, 99.1% (106/107, 95%CI
94.9-99.8%) were negative, and 1/107 was invalid. Of the 37 4-sample pools in
the 6-10% prevalence group, 100% (37/37, 95%CI 90.6-100%) were negative.
Overall in the study, 99.2% (245/247, 95% CI 97.1- 99.8%) of 4-sample pools
with 4 negative samples were negative. Two pools would have had to be
subsequently deconvoluted, with each sample being tested individually.
The efficiency with Pooled Negative Specimens (n = 247)
Positivity Rate Group| n| Results of 4-sample Pools| % Negative Percent
Agreement *
---|---|---|---
Negative| Inconclusive| Positive| Invalid
1-3%| 103| 102| 1| 0| 0| 99.0% (102/103)
95%CI 94.9-99.8%
3-6%| 107| 106| 0| 0| 1| 99.1% (106/107)
95%CI 94.9-99.8%
6-10%| 37| 37| 0| 0| 0| 100% (37/37)
95%CI 90.6-100%
Total| 247| 245| 1| 0| 1| 99.2% (245/247)
95% CI 97.1-99.8%
- Since any pool that is not negative (i.e., positive, inconclusive, and invalid) is re-tested as an individual sample, the parameter NPA affects the efficiency of 4-sample pooling
18) Pooling Validation – In Silico Sensitivity in Population with Positivity Rate 1%-10%
Quest Diagnostics conducted an in silico analysis to evaluate the effect of
4-sample pooling on the clinical sensitivity of the SARS-CoV-2 assay. This
analysis was conducted using Passing-Bablok regression analyses from the
“Pooling Validation / Sensitivity for Pools with One Positive Sample and Three
Negative Samples (n = 101)” data to calculate the Ct shift resulting from the
dilution effect of 4-sample pools (1 positive sample combined with 3 negative
samples). In the regression analysis, the X-axis displayed individual Ct
values for positive samples and the Y-axis displayed Ct values for the
corresponding pools with one positive sample and 3 negative samples. This
analysis was conducted in three populations with different positivity rates:
1-3% (n=820), 3-6% (n=1,113) and 6-10% (n=1,158). The de-identified data were
selected from sequentially tested positives based on the Quest Diagnostics
SARS-2-CoV RT-PCR molecular assay. The regression analysis was used to
calculate an interval of Ct values [X, 40] where individual samples with Ct
values within this interval would have negative results in 4-sample pools (1
positive and 3 negative) due to dilution effects. For each population, the
percent of individual samples with Ct values ranging from [X, 40] was
calculated. The X values for the N1 target in the three populations were 37.0
(1-3%), 38.3 (3-6%) and 37.65 (6-10%). The X values for the N3 target in the
three populations were 37.45 (1-3%), 38.7 (3-6%) and 38.1 (6-10%).
Of the 820 samples in the 1-3% prevalence group, 100% (820/820, 95% CI
99.5-100%) of the samples would not have negative results in 4-sample pools:
97.3% were positive (798/820, 95% CI 96.0-98.3%), 2.7% were inconclusive
(22/820, 95% CI 1.7-4.0%), and none were negative.
Of the 1,113 samples in the 3-6% prevalence group, 100% (1,113/1,113, 95% CI
99.7-100%) of the samples would not have negative results in 4-sample pools:
99.4% were positive (1,106/1,113, 99.4-99.8%), 0.6% were inconclusive
(7/1,113, 95% CI 0.3-1.3%), and none were negative.
Of the 1,158 samples in the 6-10% prevalence group, 100% (1,158/1,158, 95% CI
99.7-100%) of the samples would not have negative results in 4-sample pools:
98.5% were positive (1,141/1,158, 95% CI 97.7-99.1%), 1.5% were inconclusive
(17/1,158, 95% CI 0.9-2.3%), and none were negative.
Overall in the study, none of the 3,091 samples, if pooled, would have been
incorrectly determined to be negative (0/3,091, 95%CI 0.0-0.12%).
In Silico Sensitivity in Population with Positivity Rate 1-10% (n = 3,091)
Group #| n| Interval [X, 40] for N1| Number of samples with N1 Ct values in
the interval| Interval [X, 40] for N3| Number of samples with N3 Ct values in
the interval| # above both shifted Thresholds| Neg| Inc| Pos| % Positive
Percent Agreement*
---|---|---|---|---|---|---|---|---|---|---
1-3%| 820| [37.0, 40]| 22| [37.45, 40]| 0| 0| 0| 22| 798| 100% (820/820)
95% CI 99.5-100%
3-6%| 1,113| [38.3, 40]| 7| [38.7, 40]| 0| 0| 0| 7| 1106| 100% (1,113/1,113)
95% CI 99.7-100%
6-10%| 1,158| [37.65, 40]| 17| [38.1, 40]| 0| 0| 0| 17| 1141| 100%
(1,158/1,158)
95% CI 99.7-100%
total| 3,091| NA| 46| NA| 0| 0| 0| 46| 3045| 100% (3,091/3,091)
95% CI 99.9-100%
- Since any pool that is not negative (i.e., positive, inconclusive, and invalid) is re-tested as individual samples, the Positive Percent Agreement includes all pools that were not negative.
19) Omega Extraction Validation – Limit of Detection
Remnant respiratory specimens that were previously negative for SARS-CoV-2
RNA using the Quest Diagnostics SARS-CoV-2 Assay and the Magna Pure Method in
four different types of transport media were used in the Limit of Detection
study. The four types of transport media were VCM/UTM, UTM-RT, saline (0.9%
NaCl), PBS and Eswabs. Each pool was spiked with a positive specimen and
serially diluted with corresponding transport media. Ten aliquots were
extracted and amplified in duplicate. One run was repeated because the
instrument malfunctioned. The Omega extraction LOD (95% detection rate) is
summarized in the table below. The previously determined LOD for the Magna
Pure Method is included for comparison.
Limit of Detection – Omega Method vs Magna Pure Method
Transport Media | SARS-CoV-2 RNA LoD |
---|---|
MagnaPure Method LOD (previously determined) | Omega LOD |
≥95% Detection
(c/mL)
| Probit Analysis, 95% Detection (c/mL)| ≥95% Detection
(c/mL)
| Probit Analysis, 95% Detection (c/mL)
VCM/UTM| 100| 100| 250| 184
UTM-RT| 250| 327| 250| 215
Saline| 500| 286| 250| 124
PBS| 250| 246| 250| 195
Eswab| 500| 368| 500| 394
20) Omega Extraction Validation – Agreement with the MagnaPure Extraction
Method (n = 168)
Quest selected randomly 168 specimens that had been previously tested for
SARS-CoV-2 RNA using the Quest Diagnostics SARS-CoV-2 Assay and the Magna Pure
Method. Of the 168 specimens selected 78 were positive previously and 90 were
negative previously. Specimens included a range of transport media types
(VCM/UTM, UTMRT, PBS, Saline (0.9% NaCl) and Eswabs), and Ct values. Results
using the Omega method were compared to the previous results using the Magna
Pure Method and percent agreement was calculated. The agreement was 98.7%
(77/78, 95%CI 93.1-100%) with positive specimens, and 93.3% (84/90, 95%CI
86.0-97.5%) with negative specimens.
Agreement with the Magna Pure Extraction Method (n = 168)
Magna Pure Method | n | Omega Method | % Agreement |
---|---|---|---|
Negative | Inconclusive | Positive | Invalid |
Positive | 78 | 1 | 0 |
95%CI 93.1-100%
Negative| 90| 84| 0| 6*| 0| 93.3% (84/90)
95%CI 86.0-97.5%
- Quest Diagnostics performed an ad hoc discrepant analysis after the study and determined that 6/6 discordant specimens were low positives with the Omega extraction method.
21) Removal of RNase P Control for Unobserved Self-Collection – RNase P
Negative Rate in Health Program Population (n = 37,084)
Quest Diagnostics selected all specimens (n = 37,084) that were self-
collected without observation under a health program sponsored by an employer
or school of higher education. All specimens were tested with the Quest SARS-
CoV-2 RRT-PCR and RNase P RT-PCR. Of the 37,084 specimens, 12,303 were from
females and 24,781 were males. Of the 12,303 females, 100% (12,302/12,303 95%
CI 100-100%) had an acceptable Ct value for the RNase P marker, and 0.008%
(1/12,303) had an unacceptable Ct value (>35) for the RNase P marker. Of the
24,781 males, 100% (24,776/24,781, 95% CI 100-100%) had an acceptable Ct value
for the RNase P marker and 0.020% (5/24,781) had an unacceptable Ct value
(>35) for the RNase P marker. These data demonstrate that nearly all
participants were able to self-collect an adequate nasal swab specimen for
SARS-CoV-2 testing.
References
Contact Information, Laboratory Service Ordering, and Support
Quest Diagnostics Infectious Disease, Inc.
33608 Ortega Highway, Bldg. B-West Wing
San Juan Capistrano, CA 92675
The U.S.A. +1.949.728.4000
QuestDiagnostics.com Quest, Quest Diagnostics, any associated logos, and all
associated Quest Diagnostics registered or unregistered trademarks are the
property of Quest Diagnostics. All third-party marks—® and ™—are the property
of their respective owners. ©2020 Quest Diagnostics Incorporated. All rights
reserved. SBW1218 rev 11/12/2020
Attachment 1 – Protocol for Monitoring of Specimen Pooling Testing
Strategies
Monitoring plan for use of pooling
Laboratories should evaluate the appropriateness of the pooling and pool size
using the FDA-recommended monitoring procedure described below. Laboratories
may also consider the sensitivity of pooled testing based on the assay’s Limit
of Detection.
Ongoing assessment of positivity rate during application of the initial
selected n-sample pooling strategy:
a. If historical data on testing individual samples from the laboratory is
available:
-
The percent positivity rate, Pools, should be updated daily using a moving average of the data from pooled samples from the previous 7-10* days. If Pools is less than 85% of Individual (Ppools< 0.85 · Individual), then it is recommended that the pool size be adjusted to maximize pooling efficiency, according to the criteria in Table 1 below.
-
It is recommended that max efficiency, using Pools and Table 1 be re-assessed periodically while sample pooling is implemented by the laboratory to ensure maximum pooling efficiency
b. If historical data on testing individual samples from the laboratory is unavailable: -
After initiating the pooling strategy, calculate the initial pooling positivity rate (Pools-initial) for the first 7-10* days using a moving average of the data from the n pool testing results.
-
If Pools-initial is greater than 25%, then Dorfman pooling of patient specimens is not efficient and should cease.
-
Following the first 7-10 day period of sample pooling, calculate the pooling positivity rate (Pools-x) for the next 7-10 day period based on n pool testing results.
-
If Pools-x is less than 90% of Pool-initial (Pools-x < 0.90 · Pools-initial), it is recommended that the pool size be adjusted to maximize pooling efficiency, according to the criteria in Table 1.
-
It is recommended that max efficiency, using Pools-x and Table 14 be re-assessed periodically while sample pooling is implemented by the laboratory to ensure maximum cooling efficiency.
-
It is recommended that individuals be calculated from the previous 7-10 days, while Pools and Pools-x are calculated from data collected during a 7-10 day time frame. However, when determining if 7-10 days is appropriate, take into consideration the laboratory testing volume and percent positivity, among other factors. Note that if the number of individual or pooled positive results collected during a given time frame is less than 10, Pindividual, Ppools and Ppools-x may not be representative of the percent positivity in the testing population and the laboratory may want to consider extending the testing time period to increase the chance of capturing positives.
Table 1 Efficiency of pooling based on prevalence
P, percent of positive subjects in the tested population
|
max efficiency
(n corresponding to the maximal efficiency)
| Efficiency (F) of n-sample pooling
(a maximum increase in the number of tested patients when Dorfman n-
pooling strategy used)
---|---|---
1% – 4%| 6| 4.44 – 2.60
5% – 6%| 6| 2.32 – 2.10
7% – 12%| 6| 1.92 – 1.42
13% – 25%| 6| 1.36 – 1.01
1% – 4%| 5| 4.02 – 2.60
5% – 6%| 5| 2.35 – 2.15
7% – 12%| 5| 1.98 – 1.49
13% – 25%| 5| 1.43 – 1.04
1% – 4%| 4| 3.46 – 2.50
5% – 6%| 4| 2.30 – 2.13
7% – 12%| 4| 1.99 – 1.54
13% – 25%| 4| 1.48 – 1.07
1% – 4%| 3| 2.75 – 2.23
5% – 6%| 3| 2.10 – 1.99
7% – 12%| 3| 1.89 – 1.53
13% – 25%| 3| 1.48 – 1.10
1% – 4%| 2| 1.92 – 1.73
5% – 6%| 2| 1.67 – 1.62
7% – 12%| 2| 1.57 – 1.38
13% – 25%| 2| 1.35 – 1.07
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