So if the result is positive, it does not necessarily mean that the person has had COVID-19. While they are useful indicators of a past SARS-CoV-2 infection, these tests may also detect antibodies produced to combat other types of coronavirus. Serological tests require a blood sample. The antibodies are present in blood and tissues of anyone who has recovered from COVID-19. These detect antibodies the body produces to fight SARS-CoV-2. They cannot tell whether someone has had COVID-19 in the past and recovered. Molecular tests can only help diagnose current infections. If the second line does not appear, the result is likely negative. If this happens, the result is positive for the virus. This is a control line that shows if the test is working correctly.Īfter some time - maybe 15 minutes, depending on the specific test - another line may appear. They then insert the swab, which now contains some fluid, into a small device.Īs the fluid spreads through the device, a line should appear on a screen on the device. This is a rapid test that people can take at home using a small device that resembles a home pregnancy test.Īfter taking a sample using the swab provided, the person dips the swab in a vial of fluid. It detects proteins produced by the virus. Illustration by Diego SabogalĪn antigen test is sometimes called a lateral flow test. Share on Pinterest Ways of taking a swab for a COVID test: Check the test instructions to find out which location is recommended. If it identifies only one, it will produce an inconclusive result. This test can confirm a diagnosis of COVID-19 if it identifies two or three specific SARS-CoV-2 gene sequences. The analysis can detect signs of the virus’s genetic material in the sample. This involves a healthcare professional collecting a sample and sending it to a laboratory for testing. This is sometimes called a nucleic acid amplification test (NAAT). One type of molecular test for the virus that causes COVID-19 is a real-time polymerase chain reaction (RT-PCR) test. A person might take their own swab sample at home. Molecular tests look for signs of a current infection.Ī person performing a molecular test usually takes a sample from the back of the throat, the nose, or both using a long cotton swab. A person may have one of the following types of COVID-19 test. There are several ways to test for evidence of the virus. Image credit: Chip Somodevilla/Getty Images. Share on Pinterest A test for a SARS-CoV-2 infection often requires a swab sample.
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