AUTHOR=Daoud Ziad , McLeod Jesse , Stockman David L. 

TITLE=Higher Sensitivity Provided by the Combination of Two Lateral Flow Immunoassay Tests for the Detection of COVID-19 Immunoglobulins

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 10 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.00479

DOI=10.3389/fcimb.2020.00479

ISSN=2235-2988

ABSTRACT=SARS-Cov-2 was first identified in Wuhan- China in December 2019, it has since been declared a pandemic by the World Health Organization (WHO) in March of 2020. COVID-19 has now been reported on every continent. In the United States, the total number of confirmed reported cases of Covid-19 had exceeded 1,8 million with a total death exceeding 100,000. The most common investigational diagnostics of this diseases are RT-PCR and Serology testing. The objective of this work was to validate two commercial kits for the detection of IgM and IgG using Lateral Flow Immunoassay Tests and to study the effect of combination of both serology kits for a better detection of immunoglobulins.
195 patients presenting respiratory symptoms suggestive of infection with SARS-Cov-2 were subject to serology and molecular testing. Two Lateral Flow Immunochromatographic Assay kits were used: Healgen Scientific for SARS-CoV-2 IgM/IgG and Raybiotech for SARS-CoV-2 IgM/IgG. Sensitivity and specificity of each kit alone and in combination were determined and compared. Limit of Detection, Inter and Intra test variations, as well interfering substances and cross reactivity were also studied for both kits.
The results show sensitivities for IgM detection varying between 58.9% and 67.1% for the kits alone and 87.7% of the combination of both kits. IgG detection was not significantly affected by this combination. Both kits manifested high Specificities (99.2% to 100%). Both kits showed high clinical performance in terms of cross reactivity and interfering substances.
Our results suggest the use of combinatory testing for serology of Covid-19 after full evaluation study assessing all the parameters affecting their clinical performance before deciding of this combination