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Published on: April 6, 2021
Efficient Identification of High-Titer Anti-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibody
Khoa D Nguyen1, Oliver F Wirz1, Katharina Röltgen1
1From the Department of Pathology, Stanford University School of Medicine, Stanford, California (Nguyen, Wirz, Röltgen, Pandey, Boyd, Pham).
Context.—:
The ongoing COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has elicited a surge in demand for serologic testing to identify previously infected individuals. In particular, antibody testing is crucial in identifying COVID-19 convalescent plasma, which has been approved by the Food and Drug Administration under the Emergency Use Authorization for use as passive immunotherapy for hospitalized patients infected with COVID-19. Currently, high-titer COVID-19 convalescent plasma can be qualified by Ortho's Vitros COVID-19 IgG antibody test.
Objective.—:
To explore the use of an efficient testing method to identify high-titer COVID-19 convalescent plasma for use in treating COVID-19-infected patients and track COVID-19 positivity over time.
Design.—:
We evaluated an enzyme-linked immunosorbent assay (ELISA)-based method that detects antibodies specific to the SARS-CoV-2 receptor binding domain (RBD) with individual and pooled plasma samples and compared its performance against the Vitros COVID-19 IgG antibody test. Using the pooled RBD-ELISA (P-RE) method, we also screened more than 10 000 longitudinal healthy blood donor samples to assess seroprevalence.
Results.—:
P-RE demonstrates 100% sensitivity in detecting Food and Drug Administration-defined high-titer samples when compared with the Vitros COVID-19 IgG antibody test. Overall sensitivity of P-RE when compared with the Vitros COVID-19 IgG antibody test and our individual sample RBD-ELISA (I-RE) were 83% and 56%, respectively. When screening 10 218 healthy blood donor samples by P-RE, we found the seroprevalence correlated with the local infection rates with a correlation coefficient of 0.21 (P < .001).
Conclusions.—:
Pooling plasma samples can be used to efficiently screen large populations for individuals with high-titer anti-RBD antibodies, important for COVID-19 convalescent plasma identification.
