Longitudinal evaluation of the Abbott ARCHITECT SARS-CoV-2 IgM and IgG assays in a pediatric population

Cristina Interiano; Sheicho Muze; Brian Turner; Mark Gonzalez; Beverly Rogers; Robert Jerris; Elizabeth Weinzierl; Mohamed Elkhalifa; Van Leung-Pineda

doi:10.1016/j.plabm.2021.e00208

Longitudinal evaluation of the Abbott ARCHITECT SARS-CoV-2 IgM and IgG assays in a pediatric population

Pract Lab Med. 2021 May:25:e00208. doi: 10.1016/j.plabm.2021.e00208. Epub 2021 Feb 19.

Authors

Cristina Interiano¹, Sheicho Muze¹, Brian Turner¹, Mark Gonzalez^{1

2}, Beverly Rogers^{1

2}, Robert Jerris^{1

2}, Elizabeth Weinzierl^{1

2}, Mohamed Elkhalifa^{1

2}, Van Leung-Pineda^{1

2}

Affiliations

¹ Department of Pathology and Laboratory Medicine, Children's Healthcare of Atlanta, Atlanta, GA, USA.
² Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA.

Abstract

Background: Clinical laboratory testing has been an essential part of COVID-19 management. Serology can provide valuable information regarding a patient's exposure to virus, and may have a larger role to play as vaccines becomes available. Limited data is available on the serological response in pediatric patients. Here we investigate the use of one manufacturer's commercial assays for detecting IgM and IgG in an exclusively pediatric population.

Methods: Abbott SARS-CoV-2 IgM and IgG assays were performed on an Abbott ARCHITECT i1000. For specificity studies, we tested 78 patient specimens collected before the COVID-19 pandemic, and 66 specimens from patients who tested negative for SARS-CoV-2 nucleic acid amplification test (NAAT) during the COVID-19 pandemic. For sensitivity we tested 181 specimens from 41 patients with a positive NAAT result. Precision data was acquired for 20 days.

Results: For IgM, the highest qualitative positive agreement with molecular results was observed to be 15-30 days after a positive NAAT result or after symptom onset. For IgG, the highest positive agreement was 31-60 days after a positive NAAT result or 61-90 days after the start of symptoms. IgM started to decline 30 days after NAAT results and faded by 90 days. IgG started to decrease 60 days after a positive NAAT result.

Conclusion: The Abbott IgM and IgG assays have negative agreements of 98.7-100% relative to NAAT results. The IgM and IgG levels assayed by these methods start to decline months after positive molecular results and onset of symptoms in a pediatric population.

Keywords: COVID-19, Coronavirus Disease-19; N, Nucleocapsid protein; NAAT, Nucleic Acid Amplification Tests; RT-PCR, Reverse Transcriptase Polymerase Chain Reaction; S, Spike protein; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2.