9Health Expert, Dr. Payal Kohli, passed along the below things to know about testing for COVID-19 as cases and hospitalizations continue to rise.
As we are now solidly in our “exponential growth” phase of COVID-19 cases, I wanted to remind you all about a few key concepts to keep in mind to mitigate the spread of the virus, especially with respect to the use of testing and its limitations.
Things to know about COVID-19 testing:
- Not all rapid tests are created equal. There are only two rapid tests that have reasonably acceptable performance: SOFIA and Abbott. Check which rapid test you are getting and if it is not one of these two, it is probably not worth getting.
- The rapid test is significantly LESS sensitive than the PCR test and will always be less accurate than the PCR test. That is because the PCR test amplifies the virus’ genetic material whereas the rapid test only looks for active virus. So, rapid testing can miss up to 16% of active infections and gives a FALSE negative in ~1 in 6 cases. What I usually recommend is getting BOTH tests. If the rapid test is positive, you are done and it’s probably a true positive. If it is negative, you need to wait for the PCR test to make sure your rapid test wasn’t a false negative.
- Rapid testing performs best when you have symptoms (because there is more virus around when you have symptoms, so the rapid test is more likely to pick it up). Asymptomatic rapid testing is more likely to be inaccurate.
- A negative test (PCR or rapid) does NOT mean you are not infected with the virus. It simply means there is not enough virus around to be detected on the test at that point in time when the test was done. You could still go on to turn positive the next day or the day after. So, remember a negative test is not a “pass” to stop wearing masks, doing social distancing and washing hands, especially if you are using testing to “break your quarantine bubble” and expose yourself to someone new.
- If you have a potential exposure (i.e. you travel on a plane), you want to wait at least about 5 days or so before you get a test (preferably PCR) to see if that exposure resulted in an infection. (Of course, if you are symptomatic, you should get a test as soon as you have symptoms.)
- Getting a test soon after the exposure is likely to be misleading because the virus has not had enough time to replicate yet. So, you cannot get off the plane and get a rapid test and be reassured that you are “in the clear”.
Another type of test is a COVID-19 antibody test which checks your blood for the antibodies that may tell you if you had a past infection with the virus that causes COVID-19.
9Health has partnered with Quest Diagnostics to offer a low-cost antibody test. Click or tap here to learn more and register.
If you have a health question you can talk to a medical professional through the 9Health Neighbors Program by calling 303-698-4455, ext. 2005. Leave a message and a 9Health Medical Volunteer will call you back within 24 hours.
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