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Rapid Antigen Testing: How It Works For COVID-19 Testing

December 13, 2022

rapid antigen test

Rapid antigen testing. You’ve heard about it. Do you need it? How reliable is it compared to PCR testing? It’s cheaper, faster, and easier for businesses to administer – why? Let’s talk more about it.

How Does Rapid Antigen Testing Work?

The testing process with rapid antigen detection is simpler than it sounds:

1. A sterile swab is placed into the nose to collect a sample for testing

2. The sample is then placed in a vile with a buffer solution, ensuring all possible antigens are absorbed by the solution

3. To ensure maximum sample content is in the vile, the top of the vile should be pinched when removing the sample swab, then close the vile tightly with screw top; swab may be disposed at this point.

4. Finally, squeeze out about 3 drops of the buffer solution onto the horizontal testing tab. Results will emerge in 15-30 minutes

What Do My Test Results Mean?

Great job! You’ve now completed your rapid antigen test and have waited patiently for your results. Now it’s time to figure out how to interpret what all these lines and marks mean.

Single ‘C’ Line: Negative – Woohoo! A single line at the control indicator on your testing tab means COVID-19 was not detected on your sample.

Given the limited variability of false negatives, a second test is encouraged, but not required. Continue to monitor the potential onset of any symptoms.

Single ‘T’ Line or No Lines: Inconclusive – This is indicative of either an insufficient sample size or an error in the collection process. You should retest.

Double Lines: Positive – A line at both the ‘control’ and ‘test’ indicators is indicative of COVID-19 in a collected sample.

Given the low false positive rate of rapid antigen tests, it’s strongly advised to begin following CDC quarantining procedure and monitor symptoms.

How Do Rapid Antigen Tests Hold Up to PCR?

The accuracy of these tests is contingent on the method of detection. Antigen tests detect the presence of COVID-19 on cell surfaces. This type of detection makes it less accurate than PCR because it demands a greater number of cells already covered with virus antigens for it to be detectable by a testing kit.

Given these requirements, it’s difficult for antigen tests to detect COVID-19 before the onset of symptoms – consequently contributing to the false negative rate.

On the other hand, RT-qPCR molecular tests offer greater reliability, because it creates duplicate DNA samples to detect as little as a single viral sequence – much less of a demand than antigen testing.

The advantageous aspect of rapid antigen testing is the simplicity, speedy results turnaround, and affordability. All components of the test can be distributed in inexpensive and portable kits.

For more information about COVID-19 testing types and services, you can reach us at

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