Coronavirus Antibody Tests: Can You Trust the Results?

By May 1, 2020 May 4th, 2020 Commentary, COVID-19, In the News

Contributed by Edwin Monuki, MD, PhD, Warren L. Bostick Professor and Chair of Pathology and Laboratory Medicine at UC Irvine

A recent article in the The New York Times
focuses on an issue of grave concern among US health care providers – the flood of unapproved “lateral flow” tests for detecting COVID-19 antibodies. This flood resulted from an FDA decision to allow antibody testing without their usual approval process in order to accelerate the national response to COVID-19. Unfortunately (and not surprisingly), this also resulted in an antibody testing market that one interviewee in the NYT article called the “Wild West”. Others have referred to this market as the “Wild East”, since most of these tests come from across the Pacific. The NYT article was about a study that compared 10 of these lateral flow tests to a type of “gold standard” test known as an ELISA. This is exactly the kind of study needed now to protect the health and wellbeing of individuals and the public.

It is important to understand that the NYT article was based on a “preprint” – i.e. a paper that has been submitted, but not yet peer-reviewed and published. Nonetheless, the study was well done and its major findings are convincing, and its major finding validates our initial concerns – that many, and perhaps most, of the unapproved lateral flow tests are not good tests. Most gave too many “false positives”, which would lead patients to believe that they had COVID-19 when they actually did not. This is a big problem for the following reason. A TRUE positive test for COVID-19 will likely mean (although this remains to be proven) that patients have some level of “immunity”, or protection against getting COVID-19 again. When enough people have true immunity to COVID-19, life can return to normal. However, when people THINK they have immunity, but actually do not, they are more likely to disregard physical distancing and other public health guidelines and are more likely to actually get COVID-19 and spread it to others. If enough of this happens, then more waves of COVID-19 requiring new stay-at-home orders could become a reality.

There was also good news in the study. Some of the tests, including the gold standard ELISA, performed well with accuracies that should give reassurance to certified clinical laboratories, patients, and the public. A related piece of good news is that for the good tests, fears about false positives due to antibodies against related coronaviruses – e.g. those that cause the common cold – are lessening as we learn more. We all still have a lot to learn about these tests and COVID-19, but we have never learned or developed therapies and vaccines faster than we are right now.

About Edwin Monuki, MD, PhD:

Dr. Monuki is a neuropathologist, meaning he specializes in the diagnosis of brain diseases by examining post-mortem tissue. His research aims to improve understanding of an understudied brain tissue known as the choroid plexus in an effort to develop potential new therapies for brain diseases, such as Alzheimer’s. Dr. Monuki earned his medical and doctoral degrees from UC San Diego and currently serves as Professor and Warren L. Bostick Chair of Pathology and Laboratory Medicine for the UC Irvine School of Medicine.