A STUDY OF IMPACT OF CBNAAT IN THE DIAGNOSIS OF TUBERCULOSIS AT A RURAL BASED TERTIARY CARE TEACHING CENTRE IN INDIA

Introduction: India has the highest number of TB cases in the world and it kills more adults than any other infectious disease. The Whole genome sequencing (WGS) and its utility product the GeneXpert MTB/RIF was adopted as integral part of NTEP for quick diagnosis of MTB with resistance to rifampine. Aim & Objective: To assess the impact of CBNAAT on the other modalities i.e. smear microscopy and conventional culture and sensitivity. Material Method: This is a prospective observational, cohort study conducted at RDGMC Ujjain, MP with an enrollment of 200 cases (150 PTB and 50 EPTB) that underwent all the three investigations to fulfill inclusion criteria after a prior approval of the ethic committee and patients consent. Result: Most the cases were in productive age group of and about 66% cases had low BMI and required nutritional support. The Microscopic sensitivity and specificity were 43% and 100% as against 97% and 90% that of CBNAAT. Discussion: The yield of CBNAAT is superior and promising in smear negative, EPTB and immuno-compromised cases being of pauci bacilli status. A meticulous investigation is required for those cases that are smear positive but CBNAAT negative cases for the presence of NTM infection. A CBNAAT reporting that of very low and indeterminate is to be repeated and supportive/ or additional clinical and or radiologic findings should be incorporated. Conclusion: CBNAAT should be mandatory for the entire suspect TB cases especially for EPTB, children and immune-compromised individuals. CBNAAT has certain limitations i.e. it cannot detect drug resistance other than rifampin and non tubercular mycobacterium (NTM). The best approach for diagnosis of EPTB is to combined CBNAAT, histopathology and AFB culture. However the conventional culture and sensitivity with LJ media is gold standard cannot be over looked.