Currently, there are two main types of testing offered. Serology, or blood tests, look for antibodies in the blood from the body’s immune response to infection. There are various markers at different stages of infection. Molecular, or swab tests look for actual RNA material from the virus itself and can measure the amount of viral load. The molecular tests indicate whether you currently have an infection, while the serology tests indicate if you previously had an infection.
The COVID-19 antibody test is an immune response blood test. This type of test detects antibodies that show if you have already been exposed to and produced an immune response to COVID-19—even if you never experienced any symptoms. Previous exposure means you may now have some level of immunity to the virus, but that immunity isn’t guaranteed, and it is still unknown for what period of time it might last. Understanding your immune response gives you and your doctor the information you need to assist in making an informed decision about returning to work or activity.
A health care professional takes a blood sample, usually by drawing blood from a vein in the arm or from a capillary blood in the skin, most often a finger prick. The sample is tested to determine whether you’ve developed antibodies against the virus. The immune system produces these antibodies — proteins that are critical for fighting and clearing out the virus.
The timing and type of antibody test affects accuracy. Early in the course of infection, when the immune response is still building up in your body, the test may not detect antibodies, and could give a negative result reading for antibody markers. In order to get the most meaningful results, the antibody tests are best if you wait a full three weeks after the start of your illness.
For a complete list, please refer to the FDA EUA Test Kit Manufacturers and Commercial Laboratories Table, which is updated by the FDA daily. Under the Emergency Use Authorization, tests can be used in laboratories and at Point of Care settings once the manufacturer has validated its test and notified the FDA of its planned use. At any point the FDA may revoke the explicit or implied authorization for any reason, typically because it finds test data unreliable for medical use. No COVID-19 tests are currently APPROVED by the FDA, only AUTHORIZED for use. Our healthcare providers consistently vet and explore available testing options allowed by the FDA per the EUA, seeking convenient, yet accurate testing methods for various stages of exposure or possible infection.
Antibody tests reveal one of three results;
No protective antibodies present. This usually means an individual has not had exposure to the virus or pathogen. (There are some immunocompromised individuals that can’t adequately produce antibodies but have had exposure.)
Recently exposed–currently developing antibodies.
Exposed and recovering or recovered–protective antibodies present.
A “swab” test helps to diagnose whether you currently have an active COVID-19 infection. A nasopharyngeal swab is taken through a patient’s nose from the back of the throat and can be slightly unpleasant. Newer tests can also take samples from saliva in the mouth and throat, or from the nose. If you are currently experiencing COVID-19 symptoms or were exposed to the virus in the last 14 days, swab tests detect actual RNA material from the virus itself.
As screening becomes widely available for the general population, results from antibody tests will indicate how many people have contracted or been exposed to COVID-19 in a community, including those who didn’t show any symptoms. This aids in determining what percentage of the population has been exposed, and who might have immunity. This data can then be used to potentially alert communities to an increase in infection in their area. Over time, this data will help improve strategies to curb the COVID-19 pandemic.
