you have the virus when you actually do not — should be close to zero. Most false-positive results are thought to be due to lab contamination or other problems with how the lab has performed the test, not limitations of the test itself.
A molecular test using a deep nasal swab is usually the best option, because it will have fewer false-negative results than other diagnostic tests or samples from throat swabs or saliva. People who are in the hospital, though, may have other types of samples taken.
You may have heard about pooled testing, in which multiple samples are combined and a molecular test is performed on them. This could speed up the testing of large numbers of people and reduce the number of tests needed.
If a pooled test is negative, the people whose samples were combined are told they have a negative test and individual testing is unnecessary.
But if the pooled sample tests positive, each of the individual samples that were taken will then be tested to see which person(s) is responsible for the positive pooled result.
This approach may be particularly helpful in settings where the number of infections is low and declining, and most test results are expected to be negative.
For example, in a community where the infection seems to be under control and reopenings of schools and businesses are planned, pooled testing of employees and students could be an effective strategy.
Antigen tests
How is it done? A nasal or throat swab.
Where can you get these tests? At a hospital or doctor’s office (though it is likely home testing will soon be available).
What does the test look for? This test identifies protein fragments (antigens) from the virus.
How long does it take to get results? The technology involved is similar to