Positively Perplexed

Why are antibody tests inaccurate? The biostats, explained.

It seems complicated, but let's break it down.

Covid-19 antibody tests are tools scientists use to understand the epidemic.

But how useful they actually are right now, and if you should take one, is confusing.

Mary Altaffer/AP/Shutterstock

In some cases, a positive antibody test may only be right about half the time, reports the CDC.