Coronavirus (COVID-19): What Are the Different Types of Tests?
As coronavirus (COVID-19) spreads in communities, parents might wonder if their family should get tested, especially if someone is sick or was around a person who has the virus. Work with your doctor to figure out whether a test can be helpful.
What Are the Types of Coronavirus (COVID-19) Tests?
The two main types of tests for coronavirus look for either a current infection or a past infection.
Tests for Current Infection
To check if someone is infected with coronavirus, health care providers look for pieces of the virus in a sample of saliva (spit) or mucus. These tests can tell if the person is infected on the day of the test.
Health care providers can:
- Use a long swab (like a Q-tip) to take a sample from inside the nose (at the start of the nostrils, the middle of the nose, or the very back of the nose), the throat, the inside of the cheeks, or along the gums or tongue.
- Give the person a container to spit or cough into.
People can get the test in a doctor's office or other testing sites (such as pharmacies or pop-up sites). Some areas offer drive-thru testing, which lets people stay in their car during the test. At some testing sites, people can swab themselves following directions from the health care team. There also are special kits that families can order to do the test at home.
Depending on the type of test and where it was done, results can be ready that day or take a week or longer if the test went to a lab. Currently, home kits always go to a lab. Results might take longer if a community does many tests at the same time.
A "positive" test means a person is infected with coronavirus, and a "negative" test means they aren't infected. But sometimes the test results aren't accurate. A test result can be negative even when someone has the virus. This is why some people get a second test. Rarely, the test may be positive in someone who doesn't have the virus.
Inaccurate test results are more likely when someone is tested very early or very late in their infection. They tend to be more accurate when done a few days after someone was around an infected person or symptoms started.
Before the test, make sure you understand the instructions. For a swab test, help your child stay still so the health care provider can get a good sample. The better the sample, the more accurate the results.
Tests for Past Infection
To see if someone had coronavirus in the past, health care providers look for antibodies, which the body makes after an infection. It can tell if someone had an infection in the past, at least 2–3 weeks before the test. That's how long it takes the body to make antibodies after infection. It can't tell if the person is infected at the time of the test, which is why this test isn't used to diagnose COVID-19.
This is a blood test, with a sample taken either from a vein or a fingertip (called a "fingerstick"). Results can be ready on the same day, or up to a week later. There's no home kit for antibody testing yet.
Health experts aren't sure whether antibodies protect a person from future coronavirus infections. And if they do, it's not clear for how long.
If you or your kids get tested for coronavirus, talk with your doctor about the results and what they mean for your family. Someone with a positive test is infected and is contagious. They will need to stay home to prevent the virus from spreading to others. Sometimes people need to stay home even if their test is negative. Your doctor can tell you what your next steps are.