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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.