CONTRIBUTI SCIENTIFICI – Scientific Papers
Volume:
Biochimica Clinica 2020; 44(4) 025-026
Pubblicato on-line:
Maggio 25, 2020
DOI:
10.19186/BC_2020.054
Valutazione di IgG e IgM anti-SARS-CoV-2 su Maglumi 800 (Snibe)
AUTORI
1Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Laboratorio Analisi, Milano
2Ospedale San Raffaele, Servizio di Medicina di Laboratorio, Milano
ABSTRACT
Evaluation of Anti-SARS-CoV-2 immunoglobulin G and M on Snibe Maglumi 800
Introduction: the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a due to new beta-coronavirus causing the pandemic called Coronavirus disease 2019 (COVID-19). The evaluation of the presence of immunoglobulin G and M anti-SARS-CoV-2 (IgG and IgM) is important to understand the epidemiology of the disease and to confirm the presence of the disease when clinical signs are present, but RNA is not detected.
Methods: leftover serum samples from different types of patients were used: sera from biobank collected in 2018 as negative controls; patients recovering from the disease as positive controls; patients presenting at the Emergency Room with a positive rhino-pharyngeal swab; patients in Intensive Care Units. Anti-SARS-CoV-2 IgG and IgM were measured with MAGLUMI 2019-nCoV IgM/IgG Kits on Maglumi 800.
Results: one out of 61 expected negative resulted positive, and 2 were borderline for IgG (95% specificity, 95%CI 89.6-100), 1 positive for IgM (98.4% specificity, 95%CI 95.2-100); one out of 41 expected IgG positive resulted negative (97.6% sensitivity, 95%CI 92.8-100). All the 13 Intensive Care patients were positive for IgG, 11 for IgM. IgG were negative in 50.9% of the 55 swab positive from Emergency Room patients, while IgM were negative in 87.3%.
Discussion: sensitivity and specificity of the test appear good for IgG, some false positive is expected and low antibody titles in subjects with no disease story should be rechecked with an alternative method. IgM show a good specificity, but the unexpected low percentage of positivity in Emergency Room patients compared to IgG, pose some relevant doubts on the sensitivity of the test.
