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  • Comparison of Antibody Class-Specific SARS-CoV-2 Serologies for the Diagnosis of Acute COVID-19.

Comparison of Antibody Class-Specific SARS-CoV-2 Serologies for the Diagnosis of Acute COVID-19.

Journal of clinical microbiology (2021-01-21)
Hans Verkerke, Michael Horwath, Bejan Saeedi, Darra Boyer, Jerry W Allen, Joshua Owens, Connie M Arthur, Hirotomo Nakahara, Jennifer Rha, Kashyap Patel, Shang-Chuen Wu, Anu Paul, Nini Yasin, Jianmei Wang, Sooncheon Shin, DeAndre Brown, Katherine Normile, Lisa Cole, Mark Meyers, Heather Lin, Emily Woods, Jennifer Isaac, Kari Broder, Jenna Wade, Robert C Kauffman, Ravi Patel, Cassandra D Josephson, Stacian Reynolds, Melanie Sherman, Jens Wrammert, David Alter, Jeannette Guarner, John D Roback, Andrew Neish, Sean R Stowell
ABSTRACT

Accurate diagnosis of acute severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is critical for appropriate management of patients with this disease. We examined the possible complementary role of laboratory-developed class-specific clinical serology in assessing SARS-CoV-2 infection in hospitalized patients. Serological tests for immunoglobulin G (IgG), IgA, and IgM antibodies against the receptor binding domain (RBD) of SARS-CoV-2 were evaluated using samples from real-time reverse transcription-quantitative PCR (qRT-PCR)-confirmed inpatient coronavirus disease 2019 (COVID-19) cases. We analyzed the influence of timing and clinical severity on the diagnostic value of class-specific COVID-19 serology testing. Cross-sectional analysis revealed higher sensitivity and specificity at lower optical density cutoffs for IgA in hospitalized patients than for IgG and IgM serology (IgG area under the curve [AUC] of 0.91 [95% confidence interval {CI}, 0.89 to 0.93] versus IgA AUC of 0.97 [95% CI, 0.96 to 0.98] versus IgM AUC of 0.95 [95% CI, 0.92 to 0.97]). The enhanced performance of IgA serology was apparent in the first 2 weeks after symptom onset and the first week after PCR testing. In patients requiring intubation, all three tests exhibit enhanced sensitivity. Among PCR-negative patients under investigation for SARS-CoV-2 infection, 2 out of 61 showed clear evidence of seroconversion IgG, IgA, and IgM. Suspected false-positive results in the latter population were most frequently observed in IgG and IgM serology tests. Our findings suggest the potential utility of IgA serology in the acute setting and explore the benefits and limitations of class-specific serology as a complementary diagnostic tool to PCR for COVID-19 in the acute setting.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
IgM from human serum, reagent grade, ~95% (HPLC), buffered aqueous solution
Sigma-Aldrich
IgA from human serum, reagent grade, ≥95% (HPLC), buffered aqueous solution
Sigma-Aldrich
IgG from human serum, reagent grade, ≥95% (HPLC), buffered aqueous solution