Evaluation of serological tests for detecting SARS-CoV-2 antibodies: implementation in assessing post vaccination status

Mahmoud, D. S. A.; Ganesan, S.; Naik, s.; Bissar, S.; Al zamil, I.; Zaher, W.

Background The anti SARS CoV 2 immunological assays have promising applications in the control and surveillance of the current COVID 19 pandemic. Therefore, large number of serological assays are developed in the commercial market to measure SARS CoV 2 antibodies, which requires evaluation before their application in large scale. Objectives To evaluate the performances of commercially available serological assays for detecting SARS CoV 2 antibodies. Methods The study compared the performances of six different methods for detection of antibodies against SARS CoV 2 which includes (i) Genscript SARS CoV 2 surrogate virus neutralization test kit [Test A] (ii) Diasorin SARS CoV 2 S1 S2 IgG detection [Test B] (iii) Alinity SARS CoV 2 IgG II [Test C] (iv) Diasorin SARS CoV 2 TrimericS IgG [Test D] (v) Roche Elecsys Anti SARS CoV 2 cobas [Test E] (vi) AESKULISA (AESKU Enzyme Linked Immunosorbent Assay) [Test F] against the gold standard Plaque Reduction Neutralization Test (PRNT). Results Test E had the highest sensitivity and Test A had the highest specificity The ROC for tests A, C, D and E showed optimum cutoffs that differed from the manufacturers recommendation. Test D had the best performance considering all the performance indicators with the highest agreement with the PRNT results. Parallel testing of test A with test D and test B had the optimum performance. Conclusion Serological assays that are commercially available are very promising and show good agreement with the standard PRNT results. Studies on large samples for optimization of the assay cutoff values and cost effective evaluations on parallel testing methods are needed to make recommendations on these commercial assays.