SIMEDHealth

In the fight against COVID-19, testing is key. But there are several types of tests that can be confusing for those who don’t know the difference. We talked to SIMEDHealth Primary Care Physician David Lefkowitz, MD, about what makes these tests distinct and what tests SIMEDHealth offers.

1. What is the difference between an antibody test, an antigen test, and a viral test?

Dr. Lefkowitz says, “Antibody tests look for antibodies to a particular pathogen, in this case, SARS-CoV-2 (the COVID-19 virus). Antibodies are proteins made by your immune system in response to a pathogen. So, if you test for COVID-19 antibodies, you are trying to see if someone has been exposed to COVID-19 already. It may take days or even weeks for antibodies to become detectable. So antibody tests are not useful to diagnose an early active COVID-19 infection. The test itself is done either via a blood draw or with a drop of blood from your finger. Note, these tests are also referred to as serologic tests.”

“Antigen tests look for pieces of the virus and are typically done via a nasal swab,” Dr. Lefkowitz replied. “The nice thing about these tests is the rapid turnaround time, usually about 15 minutes. The downside is they are not as sensitive as the PCR test described below, and so they may miss people who do have the virus. Therefore, if there is a high suspicion someone has symptoms of COVID-19, such as fever, cough, shortness of breath, but they have a negative rapid antigen test, they would likely be well served to also receive a PCR to be sure whether they have COVID-19. This type of testing is also known as POC (point-of-care) testing, and it is often done  where a lot of testing needs to be completed in a short period of time, such as in medical facilities, schools, military facilities, and even airports.”

“Viral tests look specifically for the RNA of the COVID-19 virus,” explains Dr. Lefkowitz. “Depending on the type of test, viral tests use a nasal swab, oropharyngeal swab, or saliva.” He adds, “These tests can be used to diagnose active COVID-19 infection. Note, this type of testing is also known as a molecular test or a PCR test. It remains the ‘gold standard’ for diagnosing COVID-19 infections, meaning it is the most accurate.”

2. Who should get an antibody test? Who should get a viral test?

“Active infections are diagnosed with viral and antigen-type tests. These tests are also useful for screening asymptomatic people who may have COVID-19, so they don’t unknowingly spread the virus.” Dr. Lefkowitz continues, “Antibody tests are generally useful only for those who want to know if they had previous exposure to the virus. They are not useful for recent exposure. However, it is important to note that even if you test positive for the presence of COVID-19 antibodies, it doesn’t mean you have immunity against COVID-19. We don’t know yet what kind of protection these antibodies give you, or for how long. So, you still need to wear a mask, physically distance, and wash your hands. Antibody tests are also used by scientists and researchers who are studying patients who have had COVID-19.”

3. What kind of COVID-19 testing does SIMEDHealth do?

“At SIMEDHealth, we do PCR testing and antibody testing. Dr. Lefkowitz says, “Previously, we had to send the nasal PCR swabs to an outside lab, which delayed getting results. Fortunately, our SIMEDHealth laboratory has recently acquired the capability to process the PCR tests and give a timely, highly accurate result. We aim to have results out in 45 minutes. As you can imagine, both patients and our staff will find the rapid turnaround time very useful in fighting against the spread of COVID-19.”

Lastly, Dr. Lefkowitz adds, “There has been much discussion regarding COVID-19 testing since the beginning of the pandemic. We have come a long way, but there is still progress to be made. I want to remind everyone to continue to take this virus seriously, especially as we enter the colder months and flu season. If you have symptoms or have been in contact with someone tested positive for COVID-19, or the Influenza virus, you should be tested. If you have concerns, call us, we can help you.” Click here to schedule an appointment with Dr. Lefkowitz today.