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

Clin Chem Lab Med. 2021 Mar 15;59(8):1463-1467. doi: 10.1515/cclm-2021-0023. Print 2021 Jul 27.


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.

Keywords: COVID-19; RBD; SARS-CoV-2; immunoassays; neutralization; serological; spike; trimeric; vaccine.

Publication types

  • Evaluation Study

MeSH terms

  • Antibodies, Viral / blood*
  • Area Under Curve
  • Automation
  • COVID-19 / diagnosis*
  • COVID-19 / virology
  • Humans
  • Immunoassay / methods*
  • Immunoglobulin G / blood*
  • ROC Curve
  • Reagent Kits, Diagnostic
  • SARS-CoV-2 / isolation & purification
  • SARS-CoV-2 / metabolism*
  • Sensitivity and Specificity
  • Spike Glycoprotein, Coronavirus / immunology*


  • Antibodies, Viral
  • Immunoglobulin G
  • Reagent Kits, Diagnostic
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2