COVID-19 rapid diagnostic antigen test (SARS-CoV-2 Antigens)

Rapid antigen test for COVID-19 diagnosis (SARS-CoV-2 Antigens).

The Coronavirus Ag Rapid Test Cassette (Swab) is an in vitro immunochromatographic assay for the qualitative detection of SARS-CoV-2 protein nucleocapsid antigen in nasopharyngeal (NP) swab specimens directly or after the swabs have been added to means of viral transport from individuals who are suspected of having COVID-19 by their healthcare provider.

Its objective is to help in the rapid diagnosis of SARSCoV-2 infections. The Coronavirus Ag Rapid Test Cassette (Swab) does not differentiate between SARS-CoV and SARS-CoV-2.

SUMMARY AND EXPLANATION

The new coronaviruses belong to the β genus. COVID-19 is an acute respiratory infectious disease. People are generally susceptible.

Currently, patients infected by the new coronavirus are the main source of infection; Asymptomatic infected people can also be an infectious source.

According to current epidemiological research, the incubation period is 1 to 14 days, mainly 3 to 7 days. The main manifestations include fever, fatigue and dry cough. Nasal congestion, runny nose, sore throat, myalgia, and diarrhea are found in some cases.

This test is for the detection of the SARSCoV-2 nucleocapsid protein antigen. The antigen is generally detectable in upper respiratory tract samples during the acute phase of infection.

Rapid diagnosis of SARS-CoV-2 infection will help healthcare professionals treat patients and control the disease more efficiently and effectively.

PRINCIPLE OF THE TEST

The Coronavirus Ag Rapid Test Cassette (Swab) is an immunochromatographic membrane assay that uses highly sensitive monoclonal antibodies to detect the SARS-CoV-2 nucleocapsid protein in a nasopharyngeal (NP) swab.

The test strip is composed of the following parts: namely, sample pad, reagent pad, reaction membrane and absorbent pad.

The reagent pad contains colloidal gold conjugated to monoclonal antibodies against the nucleocapsid protein of SARS-CoV-2; The reaction membrane contains secondary antibodies for the SARS-CoV-2 nucleocapsid protein.

The entire strip is fixed inside a plastic device.

When the sample is added to the sample well, the dried conjugates on the reagent pad dissolve and migrate along with the sample.

If the SARS-CoV-2 antigen is presented in the sample, a complex formed between the anti-SARS-2 conjugate and the virus will be captured by the specific anti-SARS-2 monoclonal antibodies coated in the test line region ( T). The absence of the T line suggests a negative result.

To serve as a procedural control, a red line will always appear in the control line region (C) indicating that the appropriate volume of sample has been added and membrane absorption has occurred.

SUPPLIED MATERIAL

• 1 test cassette
• 1 sterile swab
• 1 extraction tube and dropper tip
• 1 workstation
• 1 tampon
• 1 package insert

MATERIAL REQUIRED BUT NOT SUPPLIED

• Clock, timer or stopwatch

WARNINGS AND PRECAUTIONS:

1. For in vitro diagnostic use only.
2. The test device should remain in the sealed bag until use.
3. Do not use the kit after its expiration date.
4. Swabs, tubes and testing devices are for single use only.
5. The extraction buffer contains a solution with a preservative (0.09% sodium azide). If solution comes into contact with skin or eyes, flush with large amounts of water.
6. Solutions containing sodium azide may react explosively with lead or copper pipes. Use large amounts of water to flush discarded solutions down a sink.
7. Do not exchange or mix components from different kit lots.
8. When collecting a nasopharyngeal swab sample, use the nasopharyngeal swab provided in the kit.
9. For accurate results, do not use bloody or overly viscous samples.
10. Wear appropriate protective clothing, gloves and eye/face protection when handling the contents of this kit.
11. Humidity and temperature can negatively affect results.
12. Used test materials should be disposed of in accordance with local regulations.

STORAGE AND STABILITY

1. The kit can be stored at room temperature or refrigerated (2-30°C).
2. Do not freeze any of the test kit components.
3. Do not use the test device and reagents after the expiration date.
4. Recap the desiccated container immediately after removing a test device.
5. Test devices that have been out of the desiccated container for more than 1 hour should be discarded.

COLLECTION OF SPECIMENS

Use the nasopharyngeal swab provided in the kit.

1. Carefully insert the swab into the patient's nostril, reaching the surface of the posterior nasopharynx that has the most secretion under visual inspection.
2. Rub over the surface of the posterior nasopharynx. Twist the swab several times.
3. Remove the swab from the nasal cavity.

SAMPLE PREPARATION PROCEDURE

1. Insert the test extraction tube into the workstation in this product. Make sure the tube is firm and reaches the bottom of the workstation.
2. Add 0.3 mL (approximately 10 drops) of sample extraction buffer into the extraction tube.
   
3. Insert the swab into the extraction tube containing 0.3 mL of extraction buffer.
4. Roll the swab at least 6 times while pressing the head against the bottom and side of the collection tube.
5. Leave the swab in the collection tube for 1 minute.
6. Squeeze the tube several times with your fingers from the outside of the tube to immerse the swab. Remove the swab. The extracted solution will be used as a test sample.
   

TRANSPORTATION AND STORAGE OF SAMPLES

Samples should be analyzed as soon as possible after collection. If specimen transport with viral transport medium (VTM) is required, minimal specimen dilution is recommended, as dilution may result in decreased test sensitivity. Whenever possible, 1 milliliter or less is best to avoid excessive dilution of the patient sample. While holding the swab, remove the cap from the tube.

Insert the swab into the tube until the break point is even with the opening of the tube. Bend the shaft of the swab at a 180-degree angle to break it at the breaking point. You may need to gently rotate the swab shaft to complete the break. Based on data generated with influenza virus, nasopharyngeal swabs in VTM are stable for up to 72 hours at 2° to 8°C.

Note: When using viral transport medium (VTM), it is important to ensure that the VTM containing the sample is warmed to room temperature. Cold samples will not flow properly and may lead to erroneous or invalid results. It will take several minutes to bring a cold sample to room temperature.

TEST PROCEDURE

Allow the test device, test sample, and buffer to equilibrate at room temperature (15-30°C) before testing.

1. Remove the test device from the sealed bag just before testing and place it on the workbench.
2. Insert a mouthpiece with filter into the sample extraction tube firmly.
3. Invert the sample extraction tube and add 4 drops (approximately 100 μL) of test sample by squeezing the extracted solution tube into the sample window.
4. Wait for the color bands to appear. The result should be read within 15 minutes. Do not interpret the result after 20 minutes.

INTERPRETATION OF RESULTS

POSITIVE:
The presence of two lines as control line (C) and test line (T) within the result window indicates a positive result.

NEGATIVE:
The presence of only one control line (C) within the result window indicates a negative result.

INVALID:
If the control line (C) is not visible within the results window after performing the test, the result is considered invalid. Some causes of invalid results are because the instructions were not followed correctly or the test may have deteriorated beyond the expiration date. It is recommended that the sample be retested using a new test.

GRADES:

1. The color intensity in the test line (T) region may vary depending on the assay concentration present in the sample. Therefore, any color tone in the test line region (T) should be considered positive. Please note that this is a qualitative test only, and cannot determine the concentration of analytes in the sample.
2. Insufficient sample volume, incorrect operating procedure or expired tests are the most likely reasons for control band failure.

QA

A procedural check is included in the test. A red line appearing in the control line region (C) is the internal control of the procedure. Confirms sufficient sample volume and correct procedural technique. Control standards are not supplied with this test. However, it is recommended that positive and negative controls be sourced from a local competent authority and tested as good laboratory practice, to confirm the testing procedure and verify test performance.

LIMITATIONS OF THE PROCEDURE

1. The etiology of respiratory infection caused by microorganisms other than SARS-CoV-2 will not be established with this test. The Coronavirus Ag Rapid Test Cassette (Swab) is capable of detecting both viable and non-viable SARS-CoV-2. The performance of the Coronavirus Ag Rapid Test Cassette (Swab) depends on the antigen load and may not correlate with viral culture results performed on the same sample.
2. Failure to follow the test procedure may adversely affect test performance and/or invalidate the test result.
3. If the test result is negative and clinical symptoms persist, additional testing with other clinical methods is recommended. A negative result does not rule out the presence of SARS-CoV-2 antigens in the sample, as they may be present below the minimum detection level of the test or if the sample was collected or transported incorrectly.
4. As with all diagnostic tests, a doctor must make a confirmed diagnosis after all clinical and laboratory findings have been evaluated.
5. Positive test results do not rule out coinfections with other pathogens.
6. Positive test results do not differentiate between SARS-CoV and SARS-CoV-2.
7. Negative results should be treated as presumptive and confirmed with an FDA-cleared molecular assay, if necessary, for clinical management, including infection control.

CLINICAL PERFORMANCE

1. Clinical sensitivity, specificity and precision

The Coronavirus Ag Rapid Test Cassette (Swab) has been evaluated with samples obtained from patients. A commercially available molecular assay was used as the reference method. The results show that the Coronavirus Ag Rapid Test Cassette (Swab) has a high overall relative accuracy.

Table 1: Coronavirus Ag Rapid Test vs PCR

Relative sensitivity: 86.7%
Relative specificity: 100%
Accuracy: 96.3%

SYMBOLOGY

ABOUT SEKURECO

Sekureco is a company that emerged in 2016 thanks to the passion of several technicians specialized in prevention and occupational safety and due to the lack of companies truly specialized in occupational protection in the market.