Product Name

SARS-CoV-2 Antigen Detection Kit (NS)

Model and Specification

Intended Use

This kit only be used for professional detection under supervision. SARS-CoV-2 Antigen Detection Kit is intended for professional use only. The kit is used for qualitative detection of SARS-CoV-2 antigen in human nasal cavity, nasopharynx and pharynx samples in vitro, based on the principle of latex immunochromatography- sandwich method. It is intended to be used as an aid in the diagnosis of people suspected of being infected with COVID-19.

COVID-19 is a new acute respiratory infectious disease and has become a major public health event in the world. The main sources of infection are patients with SARS-CoV-2 infections and asymptomatic infections, which are contagious during the incubation period and are highly contagious within 5 days of onset. Fever, dry cough, fatigue as the main clinical manifestations. Some patients have first symptoms such as loss of smell, loss of taste, etc., and a few patients have symptoms such as nasal congestion, runny nose, sore throat, conjunctivitis, myocardial pain and diarrhea.

Test Principle

This kit is based on the principle of latex immunochromatography - sandwich method to detect the antigens in the sample.

When the sample contains SARS-CoV-2 antigens, the red latex microspheres marked with SARS-CoV-2 antibodies on the sample pad combine with SARS-CoV-2 antigens to form an immune complex. When the immune complex moves to the T line on the nitrocellulose membrane, it combines with SARS-CoV-2 antibody again to form a red band. If the sample does not contain SARS-CoV-2 antigen, the above reaction will not occur and no red band will be generated at the T line. At any time of detection, the red latex microspheres labeled with chicken IgY will combine with the anti-chicken IgY antibody on the C line to form a red band.

Reagents and Materials Provided:

Materials Required but not Provided

Timer, Personal protective equipment: such as protective gloves, medical mask, goggles and lab coat. Biohazard container.

Storage and Stability

Store at temperature of 4-30°C(39.2-86°F) in a dry shady place. Avoid direct sunlight. Do not freeze the kit or its components, 18 months of shelf life (Production date to expiration date).

This product must be used in 1h at room temperature 20 to 30℃ and relative humidity between 30% and 50% after opening the inner package.

Sample Requirements

1. To avoid contamination, wear protective gloves while handling specimens when performing this test, wash hands thoroughly afterwards.

2. Collect samples as soon as possible within 7 days of symptom onset.

3. When stored in a refrigerator, all kit components must be brought to room temperature (15-30 °C) for a minimum of 30 minutes prior to performing the test. Do not open the pouch before components come to room temperature.

4. This kit is only used to detect samples collected from nasal swabs or pharyngeal swabs. Extracted specimens are stable for 4 hours in extraction buffer at room temperature.

5. It is not intended for testing other liquid sample such as nasal wash, aspirate samples or samples in viral transport media as results can be compromised by over dilution.

6. Excess blood or mucus on the swab specimen may interfere with test performance and may yield a false-positive result, avoid touching any bleeding areas when collecting specimens.

Sampling (Nasal swab sample):

Sampling (Pharynx swab sample): 

Sample processing：

Detection Procedure

Please read the instruction manual carefully before testing.

Interpretation of Results

Positive		Two colored lines appear. One red-colored line next to “C” and one red-colored line next to “T” indicate COVID-19 positive result.	The color intensity in the test region will vary depending on the amount of SARS-CoV-2 nucleocapsid protein antigen present in the sample. Any faint colored line(s) in the test region(s) should be considered as positive.
Negative		One red-colored line only next to “C” indicates a negative result.	Negative results don't preclude SARS-CoV-2 infection and they cannot be used as the sole basis for treatment or other management decisions. Should be confirmed with a molecular assay. Negative results must be combined with clinical observations, patient history, and epidemiological information.
Invalid		If the red-colored line in the control region “C” is not visible, the result is invalid.	Re-run the test one time using the remaining specimen in the extraction vial if an invalid result is obtained during initial testing.

Test Limitations

1. The test results of this product are for diagnostic aid only and cannot be used as the sole basis for confirming or excluding the diagnosis. To achieve diagnostic purposes, the results should always be assessed in combination with clinical examination, medical history, and other laboratory data.

2. This product is only used for the professional qualitative detection of SARS-CoV-2 antigen from nasal cavity, nasopharynx or pharynx swab, other specimen types may lead to incorrect results and must not be used, not for quantitative detection which provide information on the viral concentration present in the specimen.

3. This product is only for the initial screening test. The disease diagnosis should be made in conjunction with clinical observations, patient history, epidemiological information, and other laboratory evidence.

4. Subject to the limitations of the assay methodology, the questionable results should be verified with other test methodologies.

5. Failure to follow the instructions for test procedure and interpretation of test results may adversely affect test performance and/or produce invalid results.

6. Positive test results do not rule out co-infections with other pathogens.

7. False-negative test results may occur if a specimen is improperly collected transported, or handled.

8. False-negative test results may occur if significant virus mutation, improperly treated antigen degeneration.

9. False-negative test results may occur if the level of an antigen in a sample is below the detection limit of the test. Test performance depends on the amount of virus (antigen) in the sample and may or may not correlate with viral culture results performed on the same sample.

10. False negative results are more likely after eight days or longer of symptoms.

11. False positive results may occur if cross-contamination and other unverified factors.

12. Negative test results are not rule out diseases caused by other non-SARS-CoV-2 viral or bacterial infections.

13. If the differentiation of specific SARS viruses and strains is needed, additional testing, in consultation with state or local public health departments, is required.

14. The performance of this test has not yet been clinically validated for use in patients without signs and symptoms of respiratory infection, or for serial screening applications when tested twice over two or three days with at least 24 hours and no more than 48 hours between tests, and performance may differ in these populations. A study to support use for serial testing will be completed.

Warnings and Precautions

1. For in vitro diagnostic use only.

2. The instructions must be strictly followed by a trained healthcare professional to achieve accurate results. All users have to read the instruction prior to performing a test.

3. Do not use the kit if opened, damaged, or expired, keep test card sealed in its foil pouch before use.

4. To avoid cross-contamination, do not reuse the specimen collection swab.

5. Do not mix or interchange different specimens.

6. Do not dilute the collected swab with any solution except for the provided extraction buffer.

7. Inadequate or inappropriate sample collection, storage, and transport may cause false test results.

8. Samples with invalid results must be retested.

9. Clean up spills thoroughly using an appropriate disinfectant.

10. Do not store the test kit in direct sunlight.

11. Contaminated work clothing should not be allowed out of the workplace.

12. Dispose of contents/container to an approved waste disposal plant.

13. All human material should be considered potentially infectious.

Clinical Performance

In this clinical study, 510 participants were tested with SARS-CoV-2 Test Kit and RT-PCR. Two bilateral anterior nasal swab samples were collected from each participant. An RT-PCR assay for detecting SARS-CoV-2 from one swab is utilized as the comparator method for the study. All the anterior nasal swab specimens were confirmed as positive or negative and validated with Ct value by the RT-PCR. The performance of the SARS-CoV-2 Ag Test Kit as compared to the RT-PCR comparator method are presented in the table below:

454 participants were tested with SARS-CoV-2 Test Kit and RT-PCR. Two nasopharyngeal swab samples were collected from each participant. An RT-PCR assay for detecting SARS-CoV-2 from one swab is utilized as the comparator method for the study. All the nasopharyngeal swab specimens were confirmed as positive or negative and validated with Ct value by the RT-PCR. The performance of the SARS-CoV-2 Ag Test Kit as compared to the RT-PCR comparator method are presented in the table below:

481 participants were tested with SARS-CoV-2 Test Kit and RT-PCR. Two pharynx swab samples were collected from each participant. An RT-PCR assay for detecting SARS-CoV-2 from one swab is utilized as the comparator method for the study. All the nasopharyngeal swab specimens were confirmed as positive or negative and validated with Ct value by the RT-PCR. The performance of the SARS-CoV-2 Ag Test Kit as compared to the RT-PCR comparator method are presented in the table below:

Limit of Detection (Analytical Sensitivity)

A preliminary limit of detection was established using heat-inactivated SARS-CoV-2 isolate USA-WA1/2020. The strain was spiked into the pooled human nasal swab matrix obtained from multiple healthy volunteers eluted in VTM and confirmed as SARS-CoV-2 negative by RT-PCR to prepare positive samples. The estimated LoD found from the initial five-fold serial dilution test was confirmed by testing 20 replicates. The LoD was confirmed as the lowest concentration of SARS-CoV-2 that was detected ≥95% of the time. The SARS-CoV-2 Antigen Test Kit was confirmed to be 2.0×102 TCID50/mL.

Analytical Specificity: Cross Reactivity (Exclusivity) and Microbial Interference

Cross-Reactivity and Microbial Interference studies were conducted to determine if other respiratory pathogens that could be present in a nasopharyngeal sample could cause a false-positive test result, or interfere with a true positive result. A panel viruses bacteria fungus listed below, and pooled human nasopharyngeal swab was evaluated in this study. No cross-reactivity or interference was seen with the following microorganisms when tested at the concentrations listed in the table below with the exception of SARS-CoV, which resulted in positive test results due to the high homology between SARS-CoV and SARS-CoV-2 nucleocapsid proteins.

a Used for Exclusivity Testing b

Used for Microbial Interference

Cross reactivity in samples containing HKU1 coronavirus could not be conclusively ruled out through in silico comparison of the HKU1 and the SARS-CoV-2 nucleocapsid protein amino acid sequence. Additionally, the SARS-CoV-2 Nucleocapsid protein sequence was BLAST aligned on the NIH NCBI database to the entire set of proteins encoded by P. jirovecii. No significant identity was found as a result of this search and thus no interference is expected with the SARSCoV-2 Antigen Test Kit, however, cross-reactivity cannot be ruled out.

Endogenous Interfering Substances Effect

A study was conducted to determine if any substances, naturally present in respiratory specimens or that may be artificially introduced into the nasal cavity listed in the table interfere in the performance of the SARS-CoV-2 Antigen Test Kit. In addition to the materials that are found in the nasal cavity, substances that are commonly found on the hands were also tested. Test performance was evaluated in the absence and presences of SARS-CoV-2 (3x LoD). None of the substances listed in the tables below interfered with the performance of the SARS-CoV-2 Antigen Test Kit.

High-dose Hook Effect

No high dose hook effect was observed when tested with up to a concentration of 0.5×106.0 TCID50/mL of heat inactivated SARS-CoV-2 virus.

Description of Symbols

Basic information of the Manufacturer

Name: Nanjing Leading Medical Technology Co., Ltd.

Address: Unit 408-410, Block C6, 9 Xian Lin Da Xue Wei Di Rd, Xian Lin Community, Qi Xia District, Nanjing City, Jiangsu Province, China

Tel: +86 (25) 8967 4295

E-mail: postmaster@njliding.com

Website: http://www.njliding.com/

European Representative:

Name: Share Info GmbH

Add: Heerdter Lohweg 83, 40549 Düsseldorf

Tel: 0049 1795 6665 08

Dimdi Code: DE/0000049303

Version 1.0

Preparation date: 08/10/2021