- Tests for COVID-19 include the polymerase chain reaction (PCR) diagnostic test, which is a nasal swab.
- There’s also an antibody test, a blood test that may be able to tell whether you had an infection in the past.
- The incubation period for the new coronavirus is around 5 to 7 days, but it can be up to 14 days.
As more testing for COVID-19 rolls out, you may be wondering whether you should get tested.
Tests for COVID-19 include the polymerase chain reaction (PCR) diagnostic test, which is a nasal swab. There’s also the antibody test, a blood test that can tell whether you had an infection in the past.
So, should you wait till you have symptoms to go ahead and get tested? Or is it worth it to see whether you had an infection in the past?
People exposed to the virus who have had close contact with a confirmed case should get tested whether or not they have symptoms, Amira Roess, PhD, a professor of global health and epidemiology at George Mason University, told Healthline.
“By identifying individuals who are positive early in disease progression before they develop symptoms and implementing public health interventions, we can prevent a large percentage of infections. This is key, because we have learned that asymptomatic infection is a key driver of this epidemic,” she said. “Finding asymptomatic individuals will allow us to prevent them from spreading the virus.”
On the flip side, people with no exposure history and no symptoms should not get tested, Roess adds.
The virus’s incubation period is around 5 to 7 days, but it can be up to 14 days.
If you get tested too early after exposure, it can be possible that you have a false-negative test, notes Dr. Abraar Karan, an internal medicine doctor at the Brigham and Women’s Hospital and Harvard Medical School.
A positive polymerase chain reaction (PCR) means that you have detectable viral RNA. “This does not necessarily say if you are infectious,” Karan said.
Despite a positive PCR, studies have shown for some people there was little to no culturable virus after about 9 to 10 days. This means a person had an infection with the virus but tested positive long after they were no longer infectious to others.
However, PCR can remain positive for several weeks after active infection. “This means you are detecting viral RNA but not that you are infectious to others,” Karan said.
The Centers for Disease Control and Prevention (CDC) says a positive test means you should isolate at home for 10 daysTrusted Source.
Dr. Sophia Yohe, director of the University of Minnesota Molecular Diagnostics Laboratory and medical director for the Fairview/M Health COVID-19 testing lab, points out that the test only helps if you’re going to be active in protecting yourself and others.
If you don’t plan to isolate yourself if you’re positive, the test is moot, says Yohe.