Role of Culture Free Rapid ImmunoAssay (ELISA) and Genexpert (MTB/RIF) Technology in the Diagnosis of Tuberculosis

Abstract

Introduction: Prolonged laboratory processes are major hurdles in the early diagnosis of tuberculosis. Prompt management of this disease is utmost necessary to control its spread. For this purpose, use of rapid and reliable laboratory testing methods for the diagnosis of Mycobacterium tuberculosis are crucial alongwith timely infection management and preventing its transmission to the close contact population. Aims and Objective: The aim of this study was to establish a diagnostic-connection between culture free cost effective rapid immuno-assay (IgG and IgM) and GeneXpert (MTB/RIF) technology for the detection of Mycobacterium tuberculosis within the shortest possible turnaround time. Place and Duration of Study: This cross-sectional study was carried out at Institute of Microbiology and Molecular Genetic, University of the Punjab, Pakistan in collaboration with the Department of Pulmonology and TB Outpatient Department (OPD) at Jinnah Hospital, Lahore over the time of one year (2019-2020). Material and Methods: To achieve the aim, a total of 180 (pulmonary and extra-pulmonary) samples along with blood samples were collected from clinical suspects of Tuberculosis. All collected samples were subjected to AFB microscopy, GeneXpert (MTB/RIF) assay and Enzyme-linked Immunosorbent Assay (ELISA) for IgG and IgM. The diagnostic sensitivity and specificity of both methods were determined by using the solid culture as the gold standard.Study data collected through questionnaire was entered and analyzed using Statistical Package for Social Sciences (SPSS version 20).p value of ? 0.05 was considered significant. Results: The overall sensitivity and specificity of GeneXpert (MTB/RIF) assay were 98.2 % and 82.4% respectively, whereas, for IgG (ELISA) antibodies, it was 50.0% and 76.4% and for IgM (ELISA) antibodies 50.4% and 97.1% respectively. Conclusion: It was concluded that with fully automated GeneXpert (MTB/RIF) technology, maximum sensitivity and specificity can be achieved for diagnosis of tuberculosis within 2 hours.