Long-Term Longitudinal Evaluation of Six Commercial Immunoassays for the Detection of IgM and IgG Antibodies against SARS CoV-2

Abstract

The number of serological assays for SARS-CoV-2 has skyrocketed in the past year. Concerns have been raised regarding their performance characteristics, depending on the disease severity and the time of the analysis post-symptom onset (PSO). Thus, independent validations using an unbiased sample selection are required for meaningful serology data interpretation. We aimed to assess the clinical performance of six commercially available assays, the seroconversion, and the dynamics of the humoral response to SARS-CoV-2 infection. The study included 528 serum samples from 156 patients with follow-up visits up to six months PSO and 161 serum samples from healthy people. The IgG/total antibodies positive percentage increased and remained above 95% after six months when chemiluminescent immunoassay (CLIA) IgG antiS1/S2 and electro-chemiluminescent assay (ECLIA) total antiNP were used. At early time points PSO, chemiluminescent microparticle immunoassay (CMIA) IgM antiS achieved the best sensitivity. IgM and IgG appear simultaneously in most circumstances, and when performed in parallel the sensitivity increases. The severe and the moderate clinical forms were significantly associated with higher seropositivity percentage and antibody levels. High specificity was found in all evaluated assays, but the sensitivity was variable depending on the time PSO, severity of disease, detection method and targeted antigen.

Dynamics of serum cross‐neutralization capacity against SARS‐CoV‐2 Delta variant in convalescent COVID‐19 patients

“…NS, nonsignificant, p > 0.05; *, p ≤ 0.05; **, p ≤ 0.01; ***, p ≤ 0.001; ****. p ≤ 0.0001.IgG antiS1/S2 (DiaSorin) when compared with other commercially available serological assays [9][10][11]. During the first visit, a weaker correlation between NT 50 and SARS-CoV-2 S1/S2 IgG (DiaSorin) was observed compared with previous reports 6.…”

“…Serological assays are considered one of the most practical approaches for detecting antibodies, while correlations with neutralization assays may inform on infection protection correlates. Previous reports demonstrated the superior sensitivity and specificity for CLIA IgG antiS1/S2 (DiaSorin) when compared with other commercially available serological assays 9–11 …”

COVID-19 and Laboratory Markers from Romanian Patients—A Narrative Review

“…There is a downside to using IgG/IgM antibodies in regard to the significant variability in sensitivity of tests from different companies, yet they all provide good, high specificity [ 126 ]. Following BNT162b2 vaccination, it was suggested that adiponectin would be a better marker for predicting the immune responses to the vaccine [ 55 ].…”