Testing is an important COVID-19 control measure, but the best measure is to stay home if you are sick.

In the setting of a high-risk exposure to COVID-19, testing is performed when symptoms develop. For the individual who remains asymptomatic after a high-risk exposure, we recommend testing eight days after the exposure. Evidence demonstrates that testing before eight days has a high likelihood of providing a false negative result because the viral load is not yet high enough to convert the test positive. Furthermore, a test can become positive any time after the eighth day of exposure up to and including the 14th day. That means a negative test on the eighth day (or later) during the incubation period in an asymptomatic person does not clear a quarantined person to return to work.

Waiting for symptoms to develop is the most effective method of diagnosing COVID-19 because clinical sensitivity of the test is best after the onset of symptoms. If a non-health care worker has a high-risk exposure, the individual or family should quarantine for 14 days from the day of the known exposure. If a health care worker has a high-risk exposure, the individual should undergo supervised temperature and symptom monitoring for 14 days.

Examples of high-risk exposures:

  1. Living with a COVID-19 positive person.
  2. Being exposed, without masks, to a person who has tested positive for COVID-19 in close contact (within six feet) in a closed environment for more than 15 minutes.
  3. Participating in risky behaviors including going to bars, restaurants, amusement parks, large family functions (especially when indoor) where social distancing and masking are not observed.

Testing after COVID-19 has resolved (10 days after the first symptom and 72 hours symptom free without use of fever reducing medication) is NOT RECOMMENDED. The COVID-19 molecular tests detects RNA fragments, not viable virus and the COVID-19 test may remain positive long after the virus is dead in the human body.

Several testing sites are available throughout the San Antonio area and are listed on the San Antonio Metropolitan Health District website: List of Testing Locations in Bexar County.

It is not advised to go to the emergency center at a hospital just for testing. Emergency centers at hospitals throughout the city are very busy taking care of symptomatic patients with COVID-19. If you go to one of these centers for testing, you might potentially become exposed to someone with symptomatic COVID-19 disease waiting to receive medical care.

The best defense against COVID-19 is prevention.

Prevention methods include:

  • Masking always when engaging with anyone who does not live in your home.
  • Social distancing—standing or sitting at least six feet from others.
  • Reduced trips to public places like markets and grocery stores when possible.
  • Cleaning hands frequently, including after touching surfaces, and before and after eating.

What else are infectious disease experts saying about testing? Read more.