Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19: Serologic Testing (September 2020)

Background. The availability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing has rapidly increased. Current assays use a variety of technologies, measure different classes of immunoglobulin or immunoglobulin combinations, and detect antibodies directed against different portions of the virus. The overall accuracy of these tests, however, has not been well defined. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the coronavirus disease 2019 (COVID-19) serology literature and construct best-practice guidance related to SARS-CoV-2 serologic testing. This guideline is the fourth in a series of rapid, frequently updated COVID-19 guidelines developed by IDSA. Objective. IDSA's goal was to develop evidence-based recommendations that assist clinicians, clinical laboratories, patients, and policymakers in decisions related to the optimal use of SARS-CoV-2 serologic tests in a variety of settings. We also highlight important unmet research needs pertaining to the use of anti-SARS-CoV-2 antibody tests for diagnosis, public health surveillance, vaccine development, and the selection of convalescent plasma donors. Methods. A multidisciplinary panel of infectious diseases clinicians, clinical microbiologists, and experts in systematic literature review identified and prioritized clinical questions related to the use of SARS-CoV-2 serologic tests. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. Results. The panel agreed on 8 diagnostic recommendations. Conclusions. Information on the clinical performance and utility of SARS-CoV-2 serologic tests is rapidly emerging. Based on available evidence, detection of anti-SARS-CoV-2 antibodies may be useful for confirming the presence of current or past infection in selected situations. The panel identified 3 potential indications for serologic testing, including (1) evaluation of patients with a high clinical suspicion for COVID-19 when molecular diagnostic testing is negative and ≥2 weeks have passed since symptom onset, (2) assessment of multisystem inflammatory syndrome in children, and (3) conducting serosurveillance studies. The certainty of available evidence supporting the use of serology for either diagnosis or epidemiology was, however, graded as very low to moderate. For the most updated version of these guidelines, please go to https://www.idsociety.org/covid19guidelines.