Antibody tests for COVID-19

Abstract

The SARS-CoV-2 virus caused a globally growing pandemic called coronavirus disease 2019 (COVID-19) that has disrupted social, political, and medical environments around the world. Nations are assessing ways to reopen businesses while trying to balance health care risks and economic fallouts. Strategies involving antibody testing have been proposed before phased reopening of the economy. Therefore, assessing the sensitivity and specificity of antibody tests for symptomatic and asymptomatic COVID-19 patients remains paramount to prevent COVID-19 outbreaks. The antibody tests for SARS-CoV-2 detect the presence of IgA, IgM, or IgG antibodies produced by B cells. There are four major types of antibody tests: rapid diagnostic tests, enzyme-linked immunosorbent assays, neutralization assays, and chemiluminescent immunoassays. Currently, there is no standard antibody test for detecting SARS-CoV-2 antibodies during or after exposure or infection. The antibody tests for SARS-CoV-2 have a low specificity within the first week of exposure and increase in the second and third weeks. The current data on antibody tests have several limitations in quality and the presence of bias. Specifically, many antibody tests have a high false-negative rate and a high risk of bias for participant selection, application of index tests, reference standard used, and flow and timing for antibody tests that may incorrectly report the accuracy of COVID-19 antibody tests. In this review, we summarize the current methods, sensitivity/specificity, and gaps in knowledge concerning COVID-19 antibody testing.

Keywords: Antibody; COVID-19; IgG; IgM; SARS-CoV-2; coronavirus; diagnostic tests; sensitivity; specificity.

Figure 1.

Commercially available COVID-19 diagnostic antibody tests.