Experts recommend that individuals should not eat or drink at least 30 minutes before undergoing testing to avoid inaccurate results.
Professor Azeem Majeed, head of the Department of Primary Care and Public Health at Imperial College London, stated: “The correct technique significantly impacts the results of SARS-CoV-2 tests. People should blow their noses, wash their hands, and avoid eating before sampling.” These guidelines are intended to ensure a clean sample.
Before undergoing any test, you should read the instructions on the box, as each type may differ. Most will require you to wait 30 minutes after eating or drinking before taking a sample.
Rapid test results can be influenced by many factors.
Doctor Karan Rajan explains that certain foods and drinks, such as carbonated beverages, can affect sample quality, potentially leading to false positives.
The test kit contains antibodies sensitive to the SARS-CoV-2 virus. Some liquids can alter the pH, impacting the effectiveness of those antibodies.
“That’s why you need to use a buffer solution (comprising 99.7% saline solution) to provide a stable pH for the test kit to function accurately,” Dr. Rajan explains.
Currently, the market commonly features test kits for nasopharyngeal and nasal swab samples. The latter, nasal swab sampling, is simpler.
In this method, you sit still with your head tilted back at a 70-degree angle. Gently insert the swab into your nose about 2 cm deep, rotating the swab against the nasal wall for about 3 seconds.
After sampling one nostril, use the same swab to collect a sample from the other nostril. Remove the swab and place it into a tube containing the buffer solution. Rotate and rub the swab against the sides and bottom of the tube 10 times.
Let the swab soak in the solution for 1 minute. Securely close the tube cap. Shake the tube horizontally 10 times to mix the sample thoroughly. Drop 3 drops of the sample from the tube into the sample well of the test tray.
Typically, the waiting time to read results is 15-30 minutes. Do not read the results before or after the specified time.
- Negative Result: Only the control line C appears.
- Positive Result: Both the control line C and the test line T appear.
- Invalid Result: Neither the control line C nor the test line T appears, or only the test line T appears.
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