Comparative evaluation of six immunoassays for the detection of antibodies against SARS-CoV-2
Abstract
Objectives:
Serologic techniques can serve as a complement to diagnose SARS-CoV-2 infection. The objective of our study was to compare the diagnostic performance of six immunoassays to detect antibodies against SARS-CoV-2: three lateral flow immunoassays (LFAs), one ELISA and two chemiluminescence assays (CLIAs).
Methods:
We evaluated three LFAs ( Alltest, One Step and SeroFlash ), one ELISA ( Dia.Pro ) and 34 two CLIAs ( Elecsys and COV2T ). To assess the specificity, 60 pre-pandemic sera were 35 used. To evaluate the sensitivity, we used 80 serum samples from patients with 36 positive PCR for SARS-CoV-2. Agreement between techniques was evaluated using the kappa score ( k ).
Results
All immunoassays showed a specificity of 100% except for SeroFlash (96.7%). Overall sensitivity was 61.3%, 73.8%, 67.5%, 85.9%, 88.0% and 92.0% for Alltest, One Step, SeroFlash, Dia.Pro, Elecsys and COV2T , respectively. Sensitivity increased throughout the first two weeks from the onset of symptoms, reaching sensitivities over 85% from 14 days for all LFAs, being One Step the most sensitive (97.6%), followed by SeroFlash (95.1%). Dia.Pro, Elecsys and COV2T showed sensitivities over 97% from 14 days, being 100% for COV2T . One Step showed the best agreement results among LFAs, showing excellent agreement with Dia.Pro (agreement=94.2%, k =0.884), COV2T (99.1%, k =0.981) and Elecsys (97.3%, k =0.943). Dia.Pro, COV2T and Elecsys also showed excellent agreement between them.
Conclusion
One Step, Dia.Pro, Elecsys and COV2T obtained the best diagnostic performanc e results. All these techniques showed a specificity of 100% and sensitivities over 97% from 14 days after the onset of symptoms, as well as excellent levels of agreement.
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