No. A COVID test might be negative even if you have COVID-19 if you test too early or too late after infection, or if the sample wasn’t collected properly. Keeping in the mind the time it takes to develop disease after exposure (incubation period), the best time to get tested is 5-7 days after the day you might have been exposed. For example, if you have dinner with a friend on Friday who goes on to test positive, you should count 5-7 days starting Saturday. This means you should take a test on Wednesday, Thursday, or Friday. Testing earlier than Wednesday increases the chance that your test will not be accurate.
If you had contact with someone who tested positive for COVID-19 the CDC recommends that you quarantine for 14 days, even if your COVID test is negative and you do not have symptoms. This is because the incubation period can be as long as 14 days. However, as of December 2020, local public health authorities may allow individuals to discontinue quarantine under the following circumstances:
- After 10 days provided that you are symptom free
- After 7 days if you received a negative test result day 5 or later following exposure
Note that if you shorten your quarantine, it is important to continue to watch for symptoms for up to 14 days after exposure. Check with your local health department of information on quarantining if you have been in contact with someone who has COVID-19.
If your COVID test is negative and you have symptoms of COVID-19 you should continue to isolate until at least 24 hours after your symptoms are gone.