COVID-19 Testing: Clearing the Confusion

There is much confusion around COVID testing. Let me see if I can help explain:

1.     The test to determine if you are currently infected is called a “diagnostic” (or PCR-from the technology used) test. It actually tests for genetic markers of the virus. Early in the disease, there may not be enough virus for this to be positive. This test does not indicate if you have antibodies to the virus.

2.     The test to determine if you have had the disease, even if you are not currently symptomatic, is a “serology” test. These measure the presence of antibodies to the virus. The body can take up to 2 weeks to develop measurable antibodies. Unfortunately, we do not have adequate data to fully understand what it means to be “positive”. You may or may not have immunity to infection again.

3.     Both of these tests have had issues with reliability and manufacturer variability leading to both false positives and false negatives.

4.     Diagnostic testing is mostly done to determine if someone has the disease. If you are symptomatic, this is the test you should get.

5.     Serology testing is mostly used to determine the number of people in a population who have had the disease, even if they do not or did not have major symptoms. While this may be perceived as providing peace of mind, a negative diagnostic or serology test today tells nothing about your status tomorrow.

6.     This all gets better when vaccinations are available, and we can know that most of the community is immune to the disease. Like chickenpox or whooping cough or influenza.

7.     Short of total immunity, we are less at risk when we know we have reasonable therapies to cure the disease, even if we cannot prevent it. Those are also on the horizon but not here yet.

My recommendations:

1.     If you have symptoms, call your doctor and get a diagnostic test.

2.     If you are asked to participate in a study of COVID, serology testing is likely to be done.

3.     Even if you have a “positive” serology test, you must be careful. We do not understand the immunity of this disease and we cannot say with certainty that you are immune or that you cannot infect someone else.

4.     Stay “Safer at Home” regardless of your antibody state.

5.     Continue social distancing and wearing of masks.

6.     Wash your hands after contacting foreign surfaces.

7.     Be cautious and smart.

I hope this helps.

The information changes day by day. While things are better, we still have a way to go.

Stay home, stay safe, stay well.