Tale of the Titers: Serologic Testing for SARS-CoV-2 -Yes, No, and Maybe, with Clinical Examples from the IDSA Diagnostics Committee


 Diagnosis of acute SARS-CoV-2 infection relies on detection of viral antigens or amplified viral nucleic acids. Serology, although invaluable for epidemiology, is not routinely needed clinically. However, in some settings, serologic data may have direct clinical utility: for example, in evaluation of persistent symptoms in patients without a prior diagnosis of acute infection. In contrast, SARS-CoV-2 serologic testing is sometimes used or requested in situations where existing data do not support it, such as determination of need for vaccination. Here we describe available methods of serologic testing and provide cases supported by clinical vignettes of where such tests can be helpful, as well as examples where they are not. These examples may help clarify clinical decision-making in this rapidly evolving area.