False negatives more likely with COVID-19 omiron variant, doctors say

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Posted at 7:39 AM, Jan 24, 2022
and last updated 2022-01-24 08:33:17-05

TAMPA, Fla. — “False negatives are always possible,” said Dr. Paul Nanda, Chief Medical Officer for Tampa General Hospital Urgent Care.

Experts say that’s especially true when testing for COVID-19 right now.

“With omicron specifically we’re seeing a slightly higher rate of false negatives,” said Nanda.

That’s why doctors say it all depends on when you test. Timing is crucial.

“If someone came and they said I was exposed two days ago a rapid test is more likely to be false negative at that time. You really need to wait about five days post virus exposure,” said Nanda.

Most testing sites, pharmacies and doctor's offices are using either the rapid antigen test or the PCR test.

“They both have a role and they both have advantages and disadvantages,” said Nanda.

With the rapid tests, they give you same-day results. The PCR tests are the most sensitive but it could take several days to get your results back.

“That delay can change based on how taxed the labs are and how many samples are coming in,” said Nanda.

Then there are at-home tests. False negatives are more likely with those if used incorrectly. Doctors say it’s important to follow the instructions closely and test at least twice.

“Almost all tests that are sold direct to consumers on the market are sold in two-packs because they’re testing on day one when you test and then 24 to 48 hours later to retest. Using that two-test approach with rapid tests is especially important when we’re trying to make a diagnosis to enter the community safely,” said Nanda.