COVID-19 Testing. It’s in the news every day. “We don’t have enough tests. We have tests; come get one. The test results are all mixed together making it impossible to interpret them.” Get a test. Don’t get a test. No wonder the average parent is a little confused by it all.
The Cheat Sheet for COVID-19 Testing
There are Two Things we can test for: The germ that causes COVID-19 and antibodies against the virus. There are tons of different tests, and some are more accurate than others. There are links below if you want a deeper dive into testing information we have today, June 1, 2020.
To Diagnose COVID-19 Disease In A Sick or Exposed Person
If you want to know if you have COVID-19 right now, you will get the PCR test for SARS-COV2. This ‘swab-up-the-nose’ test tells if you have the germ in your nose and throat. If you do, you could spread it to another person. Most people who get sick have symptoms about 5 days after exposure, (though it can take up to 14 days) and the PCR test is both positive and super accurate when a person is sick.
PCR tests for Antigen which is the “doctor word” for unique proteins that stick out of every virus identifying it. Polio antigens are different than coronavirus antigens. When you read about coronavirus changing or mutating, these Antigens are what’s changing.
To Determine If A Prior Illness Was COVID-19
If you want to know if you’ve already been exposed and contracted COVID-19, you need a Serology Test, also known as an Antibody Test. These are blood tests. When SARS-CoV2 infects the body, the immune system responds by making antibodies imMediately so we call these antibodies IgM. After a week or two, the body begins to make IgG antibodies that are more endurinG. These IgG antibodies usually, but not always, protect a person from a second infection with the same germ.
There are many blood tests for immunity to COVID-19 and they have vary in accuracy. No test is 100% accurate. If you’re looking for more information on sensitivity, specificity, positive and negative predictive value (and you didn’t sleep through your 8:00 statistics class), there’s a link below. If you’re still reading or you’ve skipped to the summary video, here it is:
The deeper dive to understand COVID-19 testing can be found in these reliable resources:
Check back for future updates on Coronavirus testing as the weeks go by. We want our readers to feel like they understand and have a handle on the complexity of the disease and what doctors and scientists are doing to help fight the pandemic.
Gayle Schrier Smith, MD