Covid Tests Are More Accurate If You Take Them in the Afternoon

This study came out late last year, but it’s getting more attention now that everyone’s getting free covid tests mailed to them . . .

It turns out that the time of day when you take an at-home covid test might affect how accurate it is. Researchers at Vanderbilt found tests tend to be more accurate if you test yourself in the AFTERNOON.  They say ones done in the morning and at night are usually less accurate.

False positives are pretty rare in general.  So we’re really talking about false negatives, where you DO have covid, but the test says you don’t. The study found people are TWICE as likely to have an accurate positive test result if they test in the middle of the day.

So why does the time of day matter?  They think the virus just behaves differently depending on which stage of your circadian rhythm you’re in.  That’s your internal clock, and other studies have found it’s true with other viruses.

Basically, they think more virus particles are released into our blood and mucus mid-day.  So there’s just more virus for the tests to spot. 

( / Vanderbilt)