Also known as a serological test, which tests for the presence of antibodies associated with COVID-19 in your blood. These antibodies are a product of your body’s immune response to COVID-19. They may represent increased resistance or even immunity to the virus; however, antibody tests are not used to detect active infection. Additionally, not everyone who has COVID-19 ends up with antibodies, and not everyone who has had COVID-19 has displayed symptoms. For this reason, antibody tests can give you a clearer picture of your history with COVID-19, but should not be used to diagnose an active infection.
Types of Diagnostic Tests
Within the class of diagnostic tests, there are several different types. For some diagnostic tests, technicians perform a nucleic acid amplification test (NAAT). NAATs are effective because of their ability to detect very small concentrations of a virus that other tests might miss. One such test, called an rt-PCR test, uses a nasal swab to detect the presence of COVID-19. This test can be performed by swabbing the back of the throat or the inside of the nose, either with a technician or with an at-home collection kit.
This rt-PCR test is a type of (polymerase chain reaction) PCR test, which creates copies of specific strands of DNA to detect even the smallest possible amounts of a given virus. The “rt” in rt-PCR stands for reverse transcriptase, which is used to make DNA copies of the RNA present in the COVID-19 virus to facilitate the remainder of the test.
No. This World Health Organization (WHO) notice did not change the criteria for a positive COVID-19 test.
You may have heard rumors about something called the “cycle threshold” being changed. The WHO notice was simply reaffirming that test results must be appropriately analyzed, and that some tests may need to be repeated to confirm the result, which is a common practice. It doesn’t mean that PCR tests with higher cycle thresholds are invalid or inaccurate.
The bottom line: PCR tests remain the gold standard for detecting an active COVID-19 infection. The tests have accurately detected COVID-19 cases since the pandemic began. Highly trained clinical professionals are skilled at correctly interpreting PCR test results and notices like this one from the WHO.