There has been a lot of confusion about the various types of testing currently available for COVID-19.
There are two types of COVID-19 tests: the diagnostic test, which tests for a current infection, and the antibody test, which tests for a previous infection from which you have recovered.
There are two types of diagnostic test. A molecular test, sometimes called a PCR test, looks for genetic material of the virus in a sample taken from your nose, throat or saliva.
These tests are very accurate, as long as the timing of the test and the technique in collecting the sample are done correctly. A swab of your nose will provide the most accurate sample.
Results can take a
few minutes to several days, depending on the testing site, although a rapid test is slightly less accurate and can produce a false negative result.
The other type of diagnostic test is an antigen test. This looks for viral proteins from a sample. This test is less accurate than the molecular test with an increase chance of a false negative.
If you have enough symptoms of COVID-19 and had a negative antigen test, your doctor might test you again using a molecular test or consider you a presumed positive case.
If you receive a positive test on either the molecular or the antigen test, then you have an active COVID-19 infection and should quarantine yourself, monitor your symptoms, and follow the instructions of your doctor or health department.
If you receive a negative test, it could mean several things. It could mean that you are early in your infection so there wasn’t enough of a viral load for the test to pick up the virus, or the specimen collection method didn’t obtain a quality specimen. So, if you are having COVID symptoms and test negative, you should talk to your doctor about having a repeat test or possibly quarantining as a presumed positive case.
A negative test could also mean that you did not have an active COVID infection at the time the test was taken.
An antibody test is a different type of test, in that it looks for a previous exposure to COVID through a blood test. Antibody testing is not used for diagnostic purposes, as it takes your body one to three weeks to develop antibodies to the virus, and the antibody testing is not very specific.
If you test negative for antibodies, it could mean that your body hasn’t had time to make a sufficient amount of antibodies to produce a positive test, or it could mean that you have antibodies but the test didn’t pick up them up.
If you test positive for antibodies, it is not yet known whether that will protect you from re-infection or how long that protection will last.
Your body also might have developed antibodies to a different type of coronovirus, such as the common cold, which could produce a positive antibody test. Therefore, even if you have a positive test for antibodies, you still need to follow the same precautions because there is still so much unknown.
Since this is a new virus, information and recommendations are frequently changing. For the latest and most accurate information visit CDC.gov or SCDHEC.gov.
, RN BSN BCPA is a board-certified patient advocate and owner of Nurse Advocate Partners, serving Beaufort County. KBalerna@NurseAdvocatePartners.com or NurseAdvocatePartners.com