Comparative analysis between Genexpert and AAFB smear technique in Mycobacterium tuberculosis detection in sputum samples from HIV-negative patients

Abstract

The conventional method for Mycobacterium tuberculosis diagnosis has been the AAFB smear microscopy, which is cost-effective but has limited sensitivity and specificity. On the other hand, molecular diagnostic techniques like GeneXpert have emerged, offering higher sensitivity and the additional capability to detect rifampicin resistance. This study aimed to conduct a comparative analysis between GeneXpert assay and AAFB smear microscopy in Mycobacterium tuberculosis detection in sputum specimens from HIV-negative patients. Sputum samples were collected into a sterile container and AFB microscopy was carried out through conventional stained-slide microscopy. Assays by GeneXpert were performed using the manufacturer’s guidelines. Data obtained from this research was analyzed using GraphPad Prism version 9.0. Of the 133 samples tested, the number of positives for the AAFB system was 11 (36.7%) while the number of positives for GeneXpert was 19 (63.3%). The males in this study had a higher positive rate than their female counterparts (57.9% for GeneXpert and 63.6% for AAFB). Patients who fell into the 18-27-year age group had the highest positive rate compared to other age groups (52.6% for GeneXpert and 54.5% for AAFB). This study demonstrated the superior sensitivity of the GeneXpert system over AAFB smear microscopy in detecting Mycobacterium tuberculosis among HIV-negative patients. It is recommended that the GeneXpert system be prioritized where possible in tuberculosis diagnostic protocols to improve detection rates.