There is a great deal of interest in testing for COVID-19 these days. Unfortunately, there are also a lot of yet to be answered questions about the accuracy and significance of these tests.
There are two categories of tests: diagnostic tests and antibody tests. The diagnostic tests are used to determine if you have an active COVID-19 infection. A sample of mucous is collected from your nose and tested for the COVID-19 virus. The results can be available within an hour if the test is performed at the point of care or in several days if the sample is tested in an off-site lab. These tests are accurate and reliable, particularly when the result is positive. However, there are a significant number of false negatives, which occurs when the test result is negative but the person actually has COVID-19. False negatives may occur when the sample is inadequately collected or when the sample is taken very early in the disease process. If the suspicion for COVID-19 is high and the test is negative it should be repeated and appropriate precautions taken in the meantime.
The other type of COVID-19 testing is antibody testing. A sample of blood is taken and analyzed for IgG antibodies to the COVID-19 virus. This test is performed in off-site labs and the results are generally available in several days. A positive result indicates that the person was infected with the COVID-19 virus in the past. It normally takes 10 to 18 days after the COVID-19 infection for antibodies to become detected in the blood.
Unfortunately, there is currently a great deal of controversy surrounding the accuracy of antibody testing as well as the significance of the results. There can be a significant number of false positives and false negatives depending on the test used and the prevalence of COVID-19 in the community of the person tested. Studies are underway to clarify and improve the accuracy of antibody testing. In addition, it is not known if having antibodies to the COVID-19 virus confers immunity ie. protection from a future COVID-19 infection, and studies are also underway to determine this.
At the present time, the best course of action is to contact your health care provider or VA Medical Center for your individual concerns about COVID-19. They are familiar with your medical history and situation to be best able to provide guidance.