The ability to accurately test for the presence of COVID-19 is fundamental to our current battle against the coronavirus pandemic and a necessary tool for individual safety and health. Its swift, insidious spread and relative unfamiliarity to the medical community has resulted in a flurry of research and rapidly-produced testing products.
The early samples of those products had a higher false-negative rate than usually is acceptable. Still, as more data has availed itself, COVID-19 testing has become much more extensive and reliable.
Types of COVID-19 tests
Tests fall into two general categories: those that indicate active COVID-19 infection and those that show past exposure. The former is referred to as diagnostic tests, the latter as “serologies,” or antibody tests.
Diagnostic tests can determine an active COVID-19 infection by detecting viral antigens, specific protein pieces found on the surface of the viral casing, or molecular studies that identify particular parts of the virus’ RNA (genetic material). This material is present in detectable amounts in the nasal and oral mucosa, so testing is done via nasal swab or saliva collection.
Antibody tests, performed on blood, look for COVID-19-specific antibodies that the immune system produces during and after an internal battle with the virus. If your doctor wants to determine whether you may have been exposed to the virus, an antibody test could determine this two to six weeks after exposure, even if symptoms were absent. IMPORTANT: Studies have not yet decided if or how long a positive antibody result protects against COVID-19 reinfection. Continue with the usual precautions even if you test positive.
When is the best time to get tested?
Don’t let anxiety over a potential exposure propel you out the door the instant it happens. Viruses don’t increase immediately, and being tested too early puts you at risk for a false negative. Timing is crucial; allow about five days after the first exposure or for the first symptoms to appear before diagnostic testing. If you have experienced a direction, it will take at least two weeks for the first antibodies to become detectable with serological testing. The jury is out about how long they remain in circulation, but current data seems to center around a three to six-month time frame.