Performance Evaluation of the Siemens SARS-CoV-2 Total Antibody and IgG Antibody Test

Abstract
Objective: In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated.
Methods: The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction-confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response.
Results: Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens.
Conclusion: This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.
Keywords: COVID-19; SARS-CoV-2; antibody kinetics; immunoassay; performance evaluation; serology.