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VERIFY: Testing too early can give false negative, 5-7 days after exposure is more accurate

Medical experts tend to agree testing five to seven days after probable exposure will yield the most accurate testing result, but quarantine in the meantime.

GREENSBORO, N.C. — Being proactive in combatting coronavirus is a positive -- except, in the instance, it's negative -- as in false negative.

COVID-19 testing is top of mind, a week after the Thanksgiving holiday. Health experts warned the holiday would cause a surge in cases due to indoor celebrations with people who don't live in the same households. 

RELATED: Warning: Holiday travelers should get tested and quarantine for 14 days

Triad testing sites are bracing for a continued influx of people who want to find out if they were infected at their gatherings. 

RELATED: 'Stay home as much as possible' | Guilford County Health Director urges people to take precautions to protect loved ones as COVID-19 data surges


Is it true you should wait a few days after possible exposure to get tested, to make sure your results are accurate?

Yes (as long as you quarantine in the meantime).


  • Centers for Disease Control
  • MIT Medical Center
  • Anals of Internal Medicine


The CDC's testing page explains if you test negative for COVID, that means you probably were not infected at the time of your sample's collection. However, that does not mean you will not get sick. You might test negative if you got the swab early in the infection and could test positive later in the illness.

MIT Medical cites a recent Anals of Internal Medicine study that looked into the probability of a false negative on a COVID test. On the first day after a probable exposure, the likelihood of a false negative was 100%. That percent decreased with each passing day. By day five, an infected person had only a 5% chance of a false negative. Usually, symptoms develop five to six days after exposure (if at all).

MIT's conclusion? The optimal time to test for accuracy is five to seven days after probable exposure. But, remember, you can spread the virus even before you are symptomatic, and some patients never develop symptoms. The CDC's revised guidelines released Wednesday say if you know you are exposed, you should quarantine for seven days, if you get a negative test result and 10 days if you don't get tested (as long as you aren't showing symptoms). 

RELATED: CDC shortens quarantine guideline to 10 days; 7 days with negative test


It is true you should wait a few days after probable exposure for better testing accuracy or get tested more than once in the infection window. Quarantine simultaneously for the recommended amount of time.

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