Our understanding of Covid-19 and recommendations are rapidly evolving. We are learning more about the manifestations of the illness caused by SARS-CoV-2 virus. We are also provided with greater access to testing, although not all tests are created equal.
WHAT DO ANTIBODY TESTS TELL US?
- Who has antibodies to SARS-CoV-2 virus after being infected (whether or not they experienced symptoms of Covid-19)
- Who has not yet produced an immune response to the SARS-CoV-2 virus
- Who may be able to donate blood that may help those who are currently sick with Covid-19
If you are a patient of our practice, and are interested in getting the antibody test, here are the top 2 labs we recommend based on the reported accuracy of the testing platforms they use:
1.Abbott Architect SARS-CoV-2 IgG test (from FDA.gov): AVAILABLE AT QUEST
***NOTE THAT THIS MEANS THAT IF ONE TESTS POSITIVE FOR THE ANTIBODIES, THERE IS A 7.1% CHANCE OR MORE THAT THIS IS A FALSE POSITIVE (assuming no prior symptoms or strong suspicion of SARS-CoV-2 infection).***
Does my insurance cover it? Highly Covered Test by Insurance. Self-pay price is $55 (however, per Quest, patient should not receive a bill).
Turn around time: 1-2 days
2. Roche Elecsys Anti-SARS-CoV-2 antibody (from FDA.gov): AVAILABLE AT BIOREFERENCE LABORATORIES
***NOTE THAT THIS MEANS THAT IF ONE TESTS POSITIVE FOR THE ANTIBODIES, THERE IS A 3.5% CHANCE OR MORE THAT THIS IS A FALSE POSITIVE (assuming no prior symptoms or strong suspicion of SARS-CoV-2 infection).***
3. DiaSorin Liaison SARS-CoV-2 S1/S2 IgG (from FDA.gov): AVAILABLE AT BIOREFERENCE LABORATORIES
***NOTE THAT THIS MEANS THAT IF ONE TESTS POSITIVE FOR THE ANTIBODIES, THERE IS A 12% CHANCE OR MORE THAT THIS IS A FALSE POSITIVE (assuming no prior symptoms or strong suspicion of SARS-CoV-2 infection).***
NOTE THAT BIOREFERENCE IS UNABLE TO ALLOW US TO SPECIFY THE MORE ACCURATE ROCHE TEST AT THIS TIME, SO IF YOU HAVE THE TEST THERE, IT MAY BE RUN ON THE ROCHE PLATFORM OR THE DIASORIN PLATFORM.
Does my insurance cover it? This test may be covered. Self-pay price: $55.
Turn around time: 5-7 days
It is important to note that the tables below assume a prevalence of Covid-19 to be 5% in the population and that some of the sample sizes are very small (hence the wide confidence intervals). According to current statistics, 1.5 million people in the US have Covid-19. This is 0.4% of our population. Given the lag in testing, the 0.4% is likely an underestimate. However, even if it is an underestimate, and the prevalence is closer to 5%, this is still a low prevalence. With a low prevalence of the disease in the population, the likelihood that a positive test with a given specificity is a TRUE positive is much lower compared to when prevalence is high. IDSA, the Infectious Disease Society of America addresses this problem in this publication.
To read more about the pros and cons of SARS-CoV-2 antibody testing, you may read my recent article here.
Testing for antibodies is not straightforward. There are multiple options and all tests are not created equal. Timing of testing is key.
If you would like to get tested, we can help you navigate this challenge. If you are a resident of New York and have questions about testing, or would like to get tested, you may contact our office by emailing Bridget Shaffo at firstname.lastname@example.org.