Assessment of a Laboratory-Based SARS-CoV-2 Antibody Test Among Hemodialysis Patients: A Quality Improvement Initiative

Abstract Introduction: The coronavirus disease 2019 (COVID −19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS −CoV −2) infection. Although tests to detect anti −SARS −CoV-2 antibodies have been developed, their sensitivity and specificity in hemodialysis patients have not been previously assessed. Methods: As part of a quality improvement (QI) initiative, nasopharyngeal swabs and predialysis blood samples were collected on the same day from adult patients receiving routine hemodialysis care at clinics managed by a large dialysis organization in the greater Miami, Florida region (23 − 30 Apr 2020). Polymerase chain reaction (PCR) tests for SARS −CoV −2 and chemiluminescence immunoassays for anti −SARS −CoV2 antibodies were performed according to manufacturer-specified protocols. Results: Of 715 participants in the QI initiative, 38 had symptomatology consistent with COVID −19 prior to or during the initiative. Among these, COVID −19 was PCR −confirmed in 14 and ruled out in 20, with the remaining 4 being inconclusive. Among the 34 patients with known COVID −19 status, the sensitivity and specificity of the antibody test were 57.1% and 85.0% when either antibody was considered. The remaining 677 patients had no record of symptoms consistent with COVID −19, nor any known exposure. Of these, 38 patients (5.6%) tested positive for anti-SARS-CoV-2 antibodies. Conclusions: The operational characteristics of the laboratory-based antibody test make it sufficient to rule in, but not rule out, SARS −CoV −2 infection in the appropriate clinical circumstance. A substantial proportion of dialysis patients may have had asymptomatic SARS −CoV −2 infection.