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COVID-19 virus test: MedlinePlus Medical Encyclopedia


Testing can be done in a couple of ways. For a nasopharyngeal test, you will be asked to cough before the test begins and then tilt your head back slightly. A sterile, cotton-tipped swab is gently passed through a nostril and into the nasopharynx. This is the uppermost part of the throat, behind the nose. The swab is left in place for several seconds, rotated, and removed. This same procedure may be done on your other nostril.

For an anterior nasal test, the swab will be inserted into your nostril no more than 3/4 of an inch (2 centimeters). The swab will be rotated 4 times while pressing against the inside of your nostril. The same swab will be used to collect samples from both nostrils.

Tests may be done by a health care provider at an office, drive-through, or walk-up location. Check with your local health department to find out where testing is available in your area.

At-home testing kits are also available that collect a sample using a either nasal swab or sample of saliva. The sample is then either sent to a lab for testing, or with some kits, you can get results at home. Contact your provider to see if home collection and testing is appropriate for you and if it is available in your area.

There are two types of virus tests available that can diagnose COVID-19:

  • Polymerase chain reaction (PCR) tests detect the genetic material of the virus that causes COVID-19. The samples are usually sent to a laboratory for testing, and results are available in a few days. There are also rapid PCR diagnostic tests that are run on specialized equipment on-site, for which the results are available immediately.
  • Antigen tests detect specific proteins on the virus that causes COVID-19. Antigen tests are rapid diagnostic tests, which means the samples are tested on-site, and results are available in several minutes.
  • Rapid diagnostic tests of any kind are less accurate than the regular PCR test. If you get a negative result on a rapid test, but have symptoms of COVID-19, your provider may do a non-rapid PCR test.

If you have a cough that produces phlegm, the provider may also collect a sputum sample. Sometimes, secretions from your lower respiratory tract can also be used to test for the virus that causes COVID-19.



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