WANTAI SARS-CoV-2 Ab Rapid Test Instructions

Wantai SARS-CoV-2 Diagnostics
WAN TAI SAR S-CoV-2 Ab
Rapid Test
Rapid Test for Detection of Total Antibodies t o SAR S-CoV-2
FOR SERUM / PLASMA / VENIPUNCTURE WHOLE
BLOOD SPECIMEN
INSTRUCTIONS FOR USE

WJ-2710, WJ-2750
For prescription use only.
For in vitro diagnostic use only.
For use under Food and Drug Administration’s
Emergency Use Authorization (EUA) only.

INTENDED USE

The WANTAI SARS-CoV-2 Ab Rapid Test is a lateral flow assay for the qualitative detection of total antibodies (including IgG and IgM) to SARS- CoV-2 in humans serum, plasma (dipotassium E D TA, lithium heparin, and sodium citrate), and venous whole blood. The WANTAI SARS-CoV-2 Ab Rapid Test is intended for use as an aid in identifying individuals with an adaptive immune response to SARS-CoV-2, indicating recent or prior infection. At this time, it is unknown for how long antibodies persist following infection and if the presence of antibodies confers protective immunity. The WANTAI SARS-CoV-2 Ab Rapid Test should not be used to diagnose or exclude acute SARS-CoV-2 infection. Testing is limited to laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C 263a, that meet requirements to perform moderate or high complexity tests. Results are f or the detection of SARS CoV-2 antibodies. Antibodies to SARS-CoV-2 are generally detectable in the blood several days after initial infection, although the duration of time antibodies are present post-infection is not well characterized. India iduals may have e detectable v irus present for several weeks f following the second version. Laboratories within the United States and its territories are required to report all results to the appropriate public health authorities. Samples should only be tested from individuals that are 15 day s or more post-symptom onset.
The sensitivity of the WANTAI SARS-CoV-2 AB Rapid Test early after infection is unknown. Negative results do not preclude acute SARS-CoV-2 infection. If acute infection is suspected, direct testing for SARS-CoV-2 is necessary.
False-positive results for the WANTAI SARS-CoV-2 Ab Rapid Test may occur due to cross-reactivity from pre-existing antibodies or other possible causes. Due to the risk of false-positive results, confirmation of positive results should be considered using a second, different serology assay.
The WAN TAI SARS-CoV-2 Ab Rapid Test is only for use under the Food and Drug Administration’s Emergency Use Authorization.

SUMMARY

Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by infection with the SARS-CoV-2 virus. Common signs of infection include respiratory symptoms, fever, cough, shortness of breath, and breathing difficulties. In severe cases, the infection can cause pneumonia, acute respiratory distress syndrome (ARDS), kidney failure, and death.
Coronaviruses (CoV) are a large family of viruses that cause illnesses ranging from the common cold to more severe diseases such as Middle East Respiratory
Sy syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The 2019 novel coronavirus, formerly known as 2019-nCoV and now known as SARS- CoV-2, is a new strain of coronavirus that was first identified during the recent COVID-19 pandemic.

PRINCIPLE OF THE ASSAY

The WAN TAI SARS-CoV-2 Ab Rapid Test employs a chromatographic lateral flow device in a cassette format. Colloidal gold conjugated recombinant antigens corresponding to SARS-CoV-2 are dry -immobilized at the end of the nitrocellulose membrane strip. SARS-CoV-2 antigens are bond at the Test Zone (T) and antibodies are bound at the Control Zone (C). The antigen used in the assay is the receptor-binding domain of the SARS-CoV-2 spike protein. When the specimen is added, it migrates by capillary diffusion rehydrating the gold conjugate. If present in the specimen, the SARS-CoV-2 antibody will bind with the gold conjugated antigens forming particles. These particles will continue to migrate along the strip until the Test Zone (T) where they are captured by the SARS-CoV-2 antigen generating a visible red line. If there is no SARS- CoV-2 antibody in the specimen, no red line is formed in the Test Zone (T). The gold conjugate will continue to migrate alone until it is captured in the Control Zone (C) by the antibodies aggregating in a red line, which indicates the validity of the test.

COMPONENTS

Test Cassette:
Te s t cassettes are packed in f oil pouches with desiccant.
Each f oil pouch contains 1 cassette. Single-use only.
Diluent Buffer (Code “0”, ):
3ml per vial. Buffer solution containing surfactant. The Diluent Buffer can be stored at room temperature. Stable for 9 months after opening.
Wantai External Controls (required but not provided):
WQ-COVID-R
Negative Control (Code “N”,  ): Ly lyophilized, newborn calf serum buffer.
Positive Control (Code “P”, ):

Lyophilized, monoclonal mouse anti-S-RBD antibodies in newborn calf serum buffer.
Preparation of controls: the controls should be reconstituted with distilled or deionized water to the working concentration. Add water into the ampoule according to the
volume indicated on the label of the ampoule.
The reconstituted controls can be kept at 2-8°C for no longer than 7 days. For long-term storage, the reconstituted controls should be stored at below -15°C, the freeze-thaw cycles should be not more than 5 times.
Before use, bring the reconstituted controls to room temperature and mix well.
Use of controls: add 80μl of the reconstituted control to the test cassette. DO NOT ADD DILUENT BUFFER!
One negative and one positive control should be tested for every new lot, or more frequently consistent with the good laboratory practice.

Others:
Instructions f or use
Materials required but not provided:
Clock or timer, specimen collection container, centrifuge, biohazard waste container.

SPECIMEN COLLECTION

1. Human serum, plasma or venous whole blood specimens are used for this test. Plasma or whole blood specimens containing K2EDTA, sodium citrate or lithium heparin can be used for this test.
2. Specimens containing suspended fibrin or aggregates and severe homely sis (hemoglobin content greater than 400mg/L) cannot be used, but jaundice (bilirubin content less than 1.71mmol/L) and hy hyperlipemia (trilogy carried content less than 170mmol/L) can be used.
3. Serum and plasma specimens can be refrigerated at 2-8°C for one week; In the case of long-term storage, it shall be frozen below -15°C for no more than three= weeks, and repeated freezing and thawing shall not exceed 3 times. Specimens should be brought to room temperature, and mix the specimen before testing.
4. It is recommended to test the whole blood specimen immediately after blood collection. Do not use the specimen after long-term storage.

STORAGE AND STABILITY

The WAN TAI SARS-CoV-2 Ab Rapid Test can be stored at room temperature (2-30°C, do not freeze!) for 9 months from the date of manufacture.

PRECAUTIONS AND SAFETY
The WAN TAI S AR S -CoV-2 Ab Rapid Test is
For prescription use only.
For in vitro diagnostic use only.
For Emergency Use Authorization Only. 

1. This test has not been FDA cleared or approved but has been authorized for emergency use by FDA under a EUA for use by authorized laboratories.
2. This test has been authorized only for detecting total antibodies to SARS-CoV-2, not for any other viruses or pathogens.
3. The emergency use of 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. § 360bbb3(b)(1), unless the declaration is terminated or authorization is revoked sooner.
4. This reagent is only used for in vitro testing, and the operation should be carried out in strict accordance with the instructions. Make sure that the test is not expired (EXP Date indicated on the kit box). The test cassette cannot be reused.
5. Specimens should be used within the storage times noted above to avoid non-specific reactions.
6.  Use of this test kit with sample types other than those specifically approved for use with this device may result in inaccurate test results.
7. Bring all reagents to room temperature (15-30°C) before use.
8. Do not use the components of any other type of test kit as a substitute for the components in this kit.
9. Due to the different antibody levels of the positive samples, the test line (T) may show a different color intensity. During the indicated reading time, regardless of color intensity, even very weak color should be judged as positive.
10. All the waste and specimens should be treated as contaminated and must be properly disinfected (autoclaving is preferred) before disposal. The desiccant in the aluminum f oil pouch cannot be taken internally.
11.  Use routine laboratory precautions. Do not eat, drink or smoke in the area where samples and kit reagents are handled. Avoid any contact between hands, ey es or mouth during sample collection and testing.
12. Wear protective clothing such as laboratory coats, disposable gloves, and eye protection when handling patient samples. Wash hands thoroughly after handling specimens and kit reagents.
13. At room temperature, the test cassette should be used within 30 minutes after it is taken out of the package to avoid prolonged exposure to humid air (humidity > 60%), which may affect the test result. If the kit is stored at 2-8°C, the reagent should be brought to room temperature (30 minutes) before the experiment, then open the aluminum f oil pouch for use.
14. During the test, the test cassette should be laid flat on the table, so as not to cause the lateral flow speed of the specimen to be faster (or slower) and affect the test result.
15. Always interpret the results under good lighting conditions to avoid misreading of the test results. The result read after 20 minutes is invalid.

ASSAY PROCEDURE

Place the cassette on a flat surface. Before opening, allow the test cassette to reach room temperature. Use it immediately (within 30 minutes) after opening.

1. For venous whole blood/serum/plasma specimens:
   Add 10μl of the specimen into the specimen window (S). Immediately add two drops of diluent buffer into the specimen window.

2. Read the results at 15 minutes after specimen and buffer loading, but no later than 20 minutes.

Procedure Diagram

Sap 1 For serum I plasma /whole bleed specimens
Add 10ul’of specimen into the specimen window IS).
Immediately add2 drops of diluent buffer into the specimen window IS)

Quality Control: One red line should appear next to the Control Zone (C) indicating the validity of the test. Invalid test run: If no red line appears next to the Control Zone (C), the test is invalid – discard the test and repeat with the new specimen and new cassette.
Positive Results : One red line appears next to the Test Zone (T) and another line next to the Control Zone (C) which indicates that antibodies to SARS-CoV-2 have been detected through using this test.
Negative Results : No red line appears next to the Test Zone (T) and one line appears next to the Control Zone (C) which indicates that no antibodies to SARS-CoV-2 have been detected with this test. However, this does not exclude the possibility of infection with SARS-CoV-2.

CONDITIONS OF AUTHORIZATION FOR THE  LABORATORY
The WANTAI SARS-CoV-2 Ab Rapid Test Letter of Authorization, along with the authorized Fact Sheet f or Healthcare Providers, the authorized Fact Sheet for Recipients, and authorized labeling is available on the FDA website:
https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19 -emergency-use-authorizations-medical-devices/vmetro-diagnostics-as.
Authorized laboratories using the WANTAI SARS-CoV-2 Ab Rapid Test (“y our product” in the conditions below), must adhere to the Conditions of Authorization indicated
in the Letter of Authorization as listed below:

1. Authorized laboratories* using y our product must include test result reports, all authorized Fact Sheets. Under exigent circumstances, other appropriate methods f or disseminating these FactSheets may be used, which may include mass media.
2. Authorized laboratories must use y our product as outlined in the authorized labeling. Dev nations from the authorized procedures, including the authorized clinical specimen types, authorized control materials, authorized other ancillary reagents and authorized materials required to use y our product are not permitted.
3.  Authorized laboratories that receive y our product must notify the relevant public health authorities of their intent to run y our product prior to initiating testing.
4. Authorized laboratories using y our product must have a process in place f or report test results to healthcare providers and relevant public health authorities, as appropriate.
5. Authorized laboratories must collect information on the performance of y our product and report to DMD/OHT7-OIR/OPEQ/CDRH (via email: CDRH-EUA-Reporting@fda.hhs.gov ) and Beijing Wantai Biological Pharmacy Enterprise Co., Ltd (wtexport@ystwt.com) any suspected occurrence of false pos it iv e or false-negative results and significant dev nations from the established performance characteristics of y our product of which they become aware.
6. All laboratory personnel using y our product must be appropriately trained in immunoassay techniques and use appropriate laboratory and personal protective equipment when handling this kit and use y our product in accordance with the authorized labeling. All laboratory personnel using the assay must also be trained in and be familiar with the interpretation of the results of the product.
7. Beijing Wantai Biological Pharmacy Enterprise Co., Ltd., authorized distributors, and authorized laboratories using y our product must ensure that any records associated with this EUA are maintained until otherwise notified by FDA. Such records will be made available to the FDA f or inspection upon request.
   *The letter of authorization refers to “Laboratories certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA), 42 U.S.C. §263a, that meet requirements to perform moderate or high complexity tests” as “authorized laboratories.”

PERFORMANCE DATA

1. A clinical validation study of the WANTAI SARS-CoV-2 Ab Rapid Test was conducted at three sites in China in 2020. Serum and plasma specimens were evaluated from 403 subjects. Out of the 403 samples, 132 subjects were COVID-19 cases conf med positive by an RT-PCR assay while 271 subjects were conf armed PCR negative. All patients who were conf armed positive e exhibited clinical signs or symptoms of COVID-19.

The WANTAI SARS-CoV-2 Ab Rapid Test evaluation centers

Clinical institution| PCR Positive (Cases)| PCR Negative (Cases)| Total
---|---|---|---
Site 1| 12| 0| 12
Site 2| 39| 195| 234
Site 3| 81| 76| 157
Total| 132| 271.| 403

Of the 132 positive samples, 125 were positive on the WANTAI SARS-CoV-2 Ab Rapid Test, and of the 271 negative samples, 268 were negative. The kit demonstrated the overall Positiv e Percent Agreement (PPA) of 94.70% (125/132) and the Negative Percent Agreement (NPA) of 98.89% (268/271), as indicated in the table below.

Summary of clinical evaluation results

Cases| PCR Comparator SARS-CoV-2
results| Total
---|---|---
Positive| I Negative
WANTAI
SARS-CoV-2 Ab
Rapid Test
results| Positive| 125| 3| 128
Negative| 7| 268| 275
Total| 132| 271| 403

Summary of clinical performance

It was observed that the detection rate of the kit was closely related to the time of disease onset, the kit showed a higher positive detection rate in specimens f from patients who had symptoms for longer periods of time. Therefore, the interpretation of the test results should consider the specimen’s collection time. The WANTAI SARS-CoV-2 Ab Rapid Test was evaluated with 415 samples collected over the course of time from 132 PCR-positive subjects. F or  performance calculation, only the results of the f irst
bleed from each patient are considered, the performance of the test is as f ollows:
Positive percent agreement (PPA) according to days from onset of symptoms

Days from onset
of symptoms| Total PCR
positive
specimens| Number Wantai
positive result| PPA| 95% CI
---|---|---|---|---
7| 62| 38| 61.%| 48.85%-72.42%
8 – 14| 58| 45| 78.%| 65.34%-86.41%
15| 12| 11| 92.%| 64.61%-98.51%
Total| | 132| |

The table below represents the study design and results of serial bleeds by days from the onset of symptoms.
The detection rate in serially collected specimens

Days from
onset of
symptoms| 1st serial results| 2nd serial results| 3rd serial results| 4th serial results| 5th serial results
---|---|---|---|---|---
No.
tests| No.
+| No.
tests| No.
+| No.
tests| No.
+| No.
tests| No.
+| No.
tests| No.

• 0- 7 62| 38| 15| 10| 3| 3| 0| 0| 0| 0
  8 – 14 58| 45| 67| 58| 35| 31| 8| 8| 0| 0
  1512| 11| 34| 34| 51| 49| 46| 45| 24| 24
  Total 132| | 116| | 89| | 54| | 24|

2. Independent Clinical Agreement Validation Study: The WAN TAI SARS-CoV-2 Ab Rapid Test was tested on 06/16/2020 at the Frederick National Laboratory for Cancer Research (FNLCR) sponsored by the National Cancer Institute (NCI). The test was validated against a panel of previously frozen samples consisting of 30 SARS-CoV-2
antibody-positive serum samples and 80 antibody-negative serum and plasma samples. Each of the 30 antibody-positive samples was confirmed with a nucleic acid amplification test (NAAT) and both IgM and IgG antibodies were confirmed to be present in all 30 samples. The presence of antibodies in the samples was confirmed by several orthogonal methods prior to testing with the WANTAI SARS- CoV-2 Ab Rapid Test. The presence of IgM and IgG antibodies specifically was confirmed by one or more comparator methods. Antibody-positive samples were selected at different antibody titers. All antibody-negative samples were collected prior to 2020 and include: i) Sev entry (70) samples selected without regard to clinical status, “Negatives” and ii) Ten (10) samples were selected from banked serum from HIV+ patients, “HIV+”. Testing was performed by one
an operator using one lot of the WANTAI SARS-CoV-2 Ab Rapid Test. Confidence intervals for sensitivity and specificity were calculated per a score method described in CLSI EP12-A2 (2008). For evaluation of cross-reactivity with HIV+, it was evaluated whether an increased false-positive rate among antibody-negative samples with HIV was statistically higher than the false positive rate among antibody-negative samples without HIV (for this, a confidence interval for the difference in false positive
rates were calculated per a score method described by Altman). Study results and summary statistics are presented in the following tables:
Summary results of the independent evaluation

Positive
(IgM/IgG)+| Negative
(IgM/IgG)-| Negative
HIV+| Total
Positive| .30| a 1| .0| 31
Negative| 0| 69| 10| 79
---|---|---|---|---
Total| 30| 70| 10| 110

Summary statistics of the independent evaluation

Limitations of the study :

• Samples were not randomly selected, and sensitivity and specificity estimates may not be indicative of the real-world performance of the device.
• These results are based on serum and plasma samples only and may not be indicative of performance with other sample types, such as whole blood, including finger stick blood.
• Information about anticoagulants used is not known.
• The number of samples in the panel is a minimally viable sample size that still provides reasonable estimates and confidence intervals for test performance, and the samples used may not be representativ e of the antibody profile observed in the patient populations.
  To evaluate the potential cross-reactivity of the WANTAI SARS-CoV-2 Ab Rapid Test to antibodies to other viruses that may be present in the population the following viruses and autoimmune conditions were assessed. No false-positive results were observed with the WANTAI SARS-CoV-2 Ab Rapid Te s t .

Specimen| No.| .
Lot #1
+| Lot
+| #2| Lot #3
Specificity
+ –
---|---|---|---|---|---
Flu A| 8| 0| 8| 0| 8| 0| 8| 100%
Flu B| 6| 0| 6| 0| 6| 0| 6| 100%
HCV| 6| 0| 6| 0| 6| 0| 6| 100%
HBV| 6| 0| 6| 0| 6| 0| 6| 100%
ANA| 5| 0| 5| 0| 5| 0| 5| 100%
RSV| 8| 0| 8| 0| 8| 0| 8| 100%
Rhinovirus| 6| 0| 6| 0 a| 6| 0| 6| 100%
| | | | |
Specimen| | No.| +| –| Specificity
alpha COV 229E| | 5| 0| 5| 100%
alpha COV NL63| | 5| 0| 5| 100%
beta COV 0C43| | 7| 0| 7| 100%
abeta COV HKU1| | 4| 0| 4| 100%

LIMITATIONS

1. Use of the WANTAI SARS-CoV-2 Ab Rapid Test is limited to laboratory personnel who hav e been trained. Not f or home use.

2. The test is limited to the qualitativ e detection of antibodies specific f or the SARS-CoV-2 virus. The intensity of the test line does not necessarily correlate to SARS-CoV-2 antibody titer in the specimen. This test cannot be used as a quantitative test.

3. SARS-CoV-2 antibodies may be below detectable levels in patients who have been exhibiting symptoms for less than 15 days.

4. The positive result obtained with the WANTAI SARS-CoV-2 Ab Rapid Test should not be used to diagnose or exclude acute SARS-CoV-2 infection. Any positive results must be interpreted in conjunction with the patient clinical history and another laboratory testing results. Follow-up and supplementary testing of all positive specimens with other tests is required to confirm any positive result.

5. Do not use the WANITA SARS-CoV-2 Ab Rapid Test with fingerstick blood samples.

6. Results from antibody testing should not be used to diagnose or exclude acute SARS-CoV-2 infection or to inf or infection status. An essay that directly detects the
   virus should be used to evaluate symptomatic individuals f or acute COVID-19.

7. It is not known at this time if the presence of antibodies to SARS-CoV-2 conf ers immunity to re-infection.

8. A positive result may not indicate previous SARS-CoV-2 infection. Consider other information, including clinical history and local disease prevalence, in assessing the need for a second but different serology test to confirm an adaptive immune response.

9. Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions. The sensitivity of the WANTAI SARS-CoV-2 Ab Rapid Test early after infection is unknown. False-positive results may occur due to cross-reactivity from pre-existing antibodies or other possible causes. Samples with positive results should be confirmed with alternative testing method(s) and clinical findings before a diagnostic determination is made. A negative result can occur if the quantity of the anti-SARS-CoV-2 antibodies present in the specimen is below the detection limits of the assay , or the antibodies that are detected are not present during the stage of disease in which a sample is collected.

10. This test is only used for the detection of human serum, plasma or venous whole blood specimens. This test should not be used for the screening of donated blood.

11. This test has not been validated f or cross-reactivity with anti-Haemophilus influenza-positive samples.

12. The kit should be used within 30 minutes after the aluminum foil bag is opened.

13. Testing should not be performed when the ambient temperature is higher than 30 o C or the relative humidity is higher than 70%.

14. The performance of this test has not been established in individuals that have received a COVID-19 v vaccine. The clinical significance of a positive or negative antibody result following COVID-19 vaccination has not been established, and the result from this test should not be interpreted as an indication or degree of protection from infection of to vaccination.

15. The performance of this test was established based on the evaluation of a limited number of clinical specimens collected between February 2020 and March 2020 in Beijing, China; Yunnan Province, China; and Zhejiang Province, China. The clinical performance has not been established in all circulating v variants but is anticipated to be ref lect e of the prevalent v variants in circulation at the time and location of the clinical evaluation. Performance at the time of testing may vary depending on the variants circulating, including newly emerging strains of SARS-CoV-2 and their prevalence, which change over time.

REFERENCES

1.  Ria Lassaunière, et al. Evaluation of nine commercial SARS-C oV -2 immunoassays. doi: https://doi.org/10.1101/2020.04.09.20056325

2. Juanjuan Zhao, et al. Antibody responses to SARS-C on -2 in patients of novel coronavirus disease 2019.
   doi: https://doi.org/10.1101/2020.03.02.20030189

3. Bin Lou, e t a l . Serology characteristics of SARS-C of -2 infection since the exposure and post symptoms onset.
   doi: https://doi.org/10.1101/2020.03.23.20041707

4. Fan Wu, et al. Neutralizing antibody responses to SARS-CoV-2 in a COVID-19 recovered patient cohort and their implications.
   DOI: https://doi.org/10.1101/2020.03.30.20047365

5. Ying Liu, et al. Diagnostic Indexes of a Rapid IgG/IgM Combined Antibody Test for SARS-CoV-2.
   DOI: https://doi.org/10.1101/2020.03.26.20044883

SYMBOLS

  Beijing Wantai Biological Pharmacy Enterprise Co., Ltd.
No.31 Kexueyuan Road, Changping District, Beijing 102206, China
Tel: +86-10-595288 88, Fax: +86-10-8970584 9
Website: www.ystwt.com
Email: wtexport@ystwt.com
IFU VER: EU A21/01 (March 12, 2021)

References

• 万泰生物
• Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019 | medRxiv
• Serology characteristics of SARS-CoV-2 infection since the exposure and post symptoms onset | medRxiv
• Diagnostic Indexes of a Rapid IgG/IgM Combined Antibody Test for SARS-CoV-2 | medRxiv
• Neutralizing antibody responses to SARS-CoV-2 in a COVID-19 recovered patient cohort and their implications | medRxiv
• Evaluation of nine commercial SARS-CoV-2 immunoassays | medRxiv

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