Evaluation of the automated LIAISON^® SARS-CoV-2 TrimericS IgG assay for the detection of circulating antibodies

Abstract

Objectives COVID-19 has brought about tests from many manufacturers. While molecular and rapid antigen tests are targeted for early diagnosis, immunoassays have a larger role in epidemiological studies, understanding longitudinal immunity, and in vaccine development and response. Methods The performance of the LIAISON® SARS-CoV-2 TrimericS IgG assay was evaluated against the Beckman ACCESS SARS-CoV-2 IgG assay in New Mexico, and against the Siemens ADVIA Centaur COV2G assay in New York. Discordant samples were parsed using a microneutralization assay. Results A SARS-CoV-2 antibody positivity rate of 23.8% was observed in the samples tested in New York (September 2020), while in the same month the positivity rate was 1.5% in New Mexico. Positive and negative agreement were 67.6% (95% CI 49.5–82.6%) and 99.8% (95% CI 99.5–99.9%), respectively, with the Beckman test, and 98.0% (95% CI 95.7–99.3%) and 94.8% (95% CI 93.4–96.0%), respectively, with the Siemens test. Receiver operating characteristic analysis for the detection of SARS-CoV-2 antibodies discloses an AUC, area under the curve, of 0.996 (95% CI 0.992–0.999) for the LIAISON® SARS-CoV-2 TrimericS IgG assay. The criterion associated to the Youden Index was determined to be >12.9 kAU/L with a sensitivity of 99.44% and a specificity of 99.82%. Conclusions The LIAISON® SARS-CoV-2 TrimericS IgG assay is highly sensitive and specific. The balance of these parameters, without emphasis on high specificity alone, is particularly important when applied to high prevalence populations, where a highly sensitive assay will result in reporting a lower number of false negative subjects.

Performance evaluation of three automated quantitative immunoassays and their correlation with a surrogate virus neutralization test in coronavirus disease 19 patients and pre‐pandemic controls

“…In the report evaluating two Roche anti‐SARS‐CoV‐2 assays against N or S simultaneously, 19 anti‐SARS‐CoV‐2 S showed higher sensitivity than anti‐SARS‐CoV‐2 (against N) (93.0% vs. 89.0%). In a recent report, the sensitivity of DiaSorin anti‐SARS‐CoV‐2 Trimeric S was 99.4%, which was higher than the previous version of DiaSorin anti‐SARS‐CoV‐2 against S1/S2 21 . In our study, the sensitivity was highest in Roche S and Abbott Quant (96.0%), followed by DiaSorin Trimeric S (93.6%).…”

Preliminary evidence of blunted humoral response to SARS-CoV-2 mRNA vaccine in multiple sclerosis patients treated with ocrelizumab

“…Sera were stored at − 20 °C and tested using the LIAISON® SARS-CoV-2 TrimericS IgG assay (DiaSorin S.p.A., Saluggia, Italy), an indirect chemiluminescence immunoassay (CLIA) technology for the detection of serum IgG antibodies to SARS-CoV-2 trimeric spike protein (anti-TSP IgG), including neutralizing antibodies [ 6 ]. Performance and interpretation of results were done in accordance with the manufacturer’s instructions, and the IgG titers were expressed in Binding Antibody Units (BAU), an international standard unit, with 33.8 BAU/mL as cut-off value [ 7 ].…”

Humoral response to SARS-CoV-2 mRNA vaccine in patients with multiple sclerosis treated with natalizumab

“…Sera were tested at virology laboratory of our University Hospital, using the LIAISON® SARS-CoV-2 TrimericS-IgG assay (DiaSorin-S.p.A.), for the detection of IgG antibodies to SARS-CoV-2 spike protein, including neutralizing antibodies. 11 The IgG titers were expressed in binding antibody units (BAU), with 33.8 BAU/mL as negative/positive cut-off. 12 …”