NEW HAVEN, Conn. (WTNH) – We are seeing more people getting tested for COVID-19 across the country. But how accurate are the tests?
“The tests are not perfect. Not because they are badly designed but because no test is perfect,” says Dr. Sheldon Campbell.
“Immediately after people have been infected, there is just not enough virus there for a test to detect. There is a stage there where people are developing disease but are not yet sick.”
Just as challenging, “And then there are definitely people who are not sick but still have virus around and so when do you test for those folks?”
Also problematic, the pathologist says there are those who are sick with negative results.
“It’s clear that some people for whatever reason, don’t have a lot of virus in the places we look for it. Maybe it’s more in the lungs, maybe they just don’t make enough virus but they have a big reaction to the virus.”
Antibody tests are now being rolled out to determine who has been exposed to the virus.
A big concern is the high rate of false positives.
So far, no evidence that antibodies protect people from getting infected again.
“Whether they’ve got an antibody or not, we don’t know how protected they are from subsequent infections and for how long.”
When should someone get the test for the virus?
“If I become symptomatic, that’s the best time. It’s three to seven days after you’re exposed, probably in that range.”
With at-home testing now available and more locations offering them — Dr. Campbell says be sure to discuss the result with your doctor.