Coronaviruses are a large family of viruses that can cause mild to severe illness, with symptoms ranging of those of the common cold to severe pneumonia. These are single – stranded RNA microorganisms that can be transmitted from animals to humans. Common examples are Middle East Respiratory Virus (MER-CoV) and severe acute respiratory syndrome (SARS-CoV). Some of the typical symptoms include high fever, coughing, difficulty breathing. In peple with compromised immune system the symptoms are often more severe and can lead to pneumonia, severe acute respiratory syndrome or even death.
People are infected with three types of influenza viruses, most commonly type A and type B. These viruses are highly infectious and spread through viral particles from infected people when coughing or sneezing. Common symptoms or such type of airborne diseases include fever, runny nose, sore throat, muscle and joint pain, headache, fatigues. Lung complications can cause viral pneumonia, lead to secondary illness, such as bacterial pneumonia, or exacerbate pre – existing health problems, including asthma and heart failure. In some cases, influenza viruses cause severe health issues and result in death.
The test works as a dual antibody immunoassay with two separate channels. In the first channel the SARS-CoV-2 antibody is immobilized on the membrane in the test area. Anti-SARS-CoV-2 antibody conjugated particles form complexes on the membrane near the sample well. An extract from a nasopharyngeal sample is added to the well, where it interacts with the antibody – coated particles and SARS-CoV-2 antigens present in the sample bind to antibodies. The antibody – particle complexes migrate up the membrane by capillary action where they interact with the SARS-CoV-2 antibodies on the test line and bind. The result is positive when a colored strip appears on the test line. The absence of a line in the test area means a negative result. To validate the test, a colored line should always appear in the control area, indicating that an appropriate sample volume has been added and there has been membrane permeation.
In the second channel, antibodies against influenza virus A and B are immobilized on the membrane of lines A and B respectively. Particles conjugated with antibody against influenza virus A and B form a coating on the membrane near the sample well. The extracted sample is added to the sample well where it interacts with the particles. At the same time the antigens present in the sample bind to one or both of the antibodies. The antibody – particle complexes migrate up the membrane by capillary action, where they interact with and bind to the influenza virus A and / or B antibodies on the respective test lines. There is a positive result when a colored strip appears on test line A and / or B. The absence of any line in the test area means a negative result. To validate the result, a colored line should always appear in the control area, indicating that an appropriate sample volume has been added and there has been membrane permeation.
The test device contains antibodies against SARS-CoV-2 and influenza A and B.
- Individually packed test items
- Extraction buffer
- Extraction tube
- Instruction manual
Follow good laboratory procedures for handling specimens and kits.
Treat the device and all specimens as potentially infectious.
Follow local regulations for proper sample disposal.
Wear protective clothing, including a lab coat, disposable gloves and safety glasses when performing the test.
WARNIGN: Viral Transport Medium (VTM) can affect test results. Do not store samples in VTM. Humidity and temperature can adversely affect results.
Storage and Shelf Life
The kit can be stored at room temperature or in a refrigerator (2 – 30 degrees C). The test should not be used if the sealed patch is broken. Do not use after the expiration date. Do not freeze.
Sample Collection and Storage
The test is performed with a nasopharyngeal sample.
Sampling: insert the swab into the patient’s nasal cavity and push to the back of the nasopharynx. Rub he tampon on the back if the nasopharynx and slowly pull it out with a twist.
Transportation and storage
The samples should be tested as soon as possible. If they are not immediately tested, the tampons have to be tightly sealed in a dry sample container. In such conditions they can be stored for up to 8 hours at room temperature (15 – 30°C) or 24 hours at 2 – 8°C.
- Use the extraction tubes and buffer from the kit.
- Arrange the tubes on the tube rack and add 350 350 µl buffer. Place the dry sample swab into the buffer. While holding the swab head below the surface of the buffer, gently rotate the tube or mix the liquid with the swab to release the antigens into the extraction buffer.
- Press the swab against the wall of the tube, then remove the swab by squeezing the sides of the tube around it in order to release as much buffer as possible.
- Place the cap on the extraction tube firmly. See illustration below.
- The extracted sample is stable for 2 hours at room temperature (15 – 30°C) or 24 hours at 2 – 8°C.
- Leave the extracted samples, controls and sealed test to equilibrate to room temperature (15 – 30°C).
- Remove the test from the sealed bag, place it on a clean flat surface and use it immediately (no later than an hour after opening).
- Tilt the tube and place 3 drops of extracted sample (approximately 100 µl) into each of the sample wells. Turn on the timer.
- Wait for colored lines to appear. Report the results after 15 minutes. Do not interpret results in case 20 minutes have passed.
Positive result for SARS-CoV-2: Two clear colored lines appear in the left window. One strip appears on the control line (C) and one strip appears on the test line (T). This result indicates detection of SARS-CoV-2 antigens.
Positive for Influenza A: Two clear colored lines appear in the right reading window. One strip appears on control line (C) and one strip appears on the influenza A test line (A). This result indicates detection of influenza A antigen.
Positive for Influenza C: Two clear colored lines appear in the right reading window. One strip appears on the control line (C) and one strip appears on the influenza B test line (B). This result indicates detection of influenza B antigen.
Positive for Influenza A and Influenza B: Three clear colored lines appear in the right reading window. One strip (C) appears on the control line, one strip appears on the influenza A test line, and one strip forms on the influenza B test line. This result indicates detection of both influenza A and influenza B antigens.
*NOTE: The color intensity of the test lines varies depending on the concentration of antigens in the sample. Therefore, any shade of the color that appears on the test lines should be considered positive.
Negative result: A single colored line appears on the control line (C). No color lines are noticeable in the test areas.
No control line appears. Insufficient sample volume or incorrect procedural technique are among the most common reasons for missing control lines. Review the procedure and repeat the test using a new device. If the problem persists, stop using the kit immediately and contact your local distributor.
A procedural control is included in the test. A colored line appears in the control area (C) in the internal procedural control. This confirms that the volume of the sample is sufficient and the procedure technique is correct. No quality controls are provided with this kit.
The procedure for analysis and interpretation of analysis results must be strictly followed when testing for the presence of antigens of SARS-CoV-2 and influenza A and B in individual patients. Failure to follow the procedure may produce inaccurate results.
Swab samples stored in VTM cannot be used in the 2019-nCoV and influenza A+B antigen detection test. Samples extracted by the PCR amplification procedure cannot be used in this test.
The 2019-nCoV and Influenza A+B test is limited to the qualitative detection of antigens of SARS-CoV-2 and influenza A and B viruses in swab-extracted specimens for the differential diagnosis of COVID-19 and influenza. The intensity of the test strips does not have a linear correlation with the concentration of antigens in the samples.
A negative result for an individual patient indicates the absence of a detectable level of SARS-CoV-2 antigens, influenza A and influenza B antigens, but it does not exclude possible exposure or infection with these viruses. If symptoms persist, repeat the test with a new smear after 2-4 days or an alternative test, such as RT-PCR.
If the sample contains blood or an excessive amount of mucus, this can lead to false positive results, and false negative results. Invalid results can be obtained after improper collection, extraction or storage of the sample.
The results obtained with this test should not be used as the sole criterion for the diagnosis of SARS-CoV-2 infection, but should be used in conjunction with other diagnostic procedures and clinical findings.
Seven levels of standard material for SARS-CoV-2 and influenza A and B, including negative, SARS-CoV-2 weak antigen, SARS-CoV-2 strong antigen, influenza A weak antigen, influenza A strong antigen, influenza B weak antigen and influenza B strong antigen were used to determine the intralaboratory and interlaboratory precision of the test. Ten replicates of each level were tested each day on 3 consecutive days. The results for each resample for each level were correct, consistent with the determined result for the standard sample, with an accuracy greater than 99%.
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