Open AccessCROSS-REACTIVITY OF COVID-19 IGG ASSAY WITH KNOWN IMMUNE-MEDIATED AND INFECTIOUS DISORDERS
Author(s) -
Nayab Zehra,
Muhammad Sohaib Khan,
Hijab Batool,
Omar Rasheed Chughtai,
Akhtar Sohail Chughtai,
Muhammad Usman
Publication year - 2021
Publication title -
pakistan armed forces medical journal
Language(s) - English
Resource type - Journals
eISSN - 2411-8842
pISSN - 0030-9648
DOI - 10.51253/pafmj.v6i6.5685
Subject(s) - medicine , immunology , serology , dengue fever , antibody , virology , rubella , syphilis , hepatitis a , rheumatoid factor , hepatitis , vaccination , measles , human immunodeficiency virus (hiv)
Objective: To assess the cross-reactivity of COVID-19 IgG assay with known immune-mediated and infectious disorders and evaluate for any false-positive reactions to determine the specificity of the serological assay.
Study Design: Cross-sectional analytical study.
Place and Duration of Study: Department of Chemical Pathology, Chughtai Institute of Pathology, Lahore Pakistan, from Sep to Oct 2020.
Methodology: A total of 116 samples were included in the study of both males and females. Diagnosed cases of typhoid fever, viral hepatitis, systemic lupus erythematosus (SLE), syphilis, multiple connective tissue disorders (MCTD), varicella-zoster infection, rabies, toxoplasmosis, epstein-barr virus (EBV) infection, rubella, rheumatoid arthritis, AIDS, cytomegalovirus (CMV) infection and dengue fever were included in the study. Three samples of multiparous women aged more than 40 years were also included in the study. IgG antibody levels were measured against SARS-CoV-2 with a cut-off index of 1.4.
Results: Out of 116, only 3 (2%) samples were reactive for IgG against SARS-CoV-2. The categories showing cross-reactivity were typhoid, hepatitis C, and CMV. All specimens showing cross-reactivity were of females. Assay under consideration showed a specificity of 97.4%.
Conclusion: Cross-reactivity was seen in pre-pandemic cases of infectious diseases with COVID-19 IgG antibody assay. Medical lab professionals must verify the serological assays before use in the clinical laboratory to avoid false-positive results.