EVALUATION OF DIAGNOSTIC PERFORMANCE OF GENEXPERT MTB IN CEREBROSPINAL FLUID FOR EARLY DIAGNOSIS OF TUBERCULOUS MENINGITIS

BACKGROUND
\nTuberculous meningitis (TBM) is the most severe form of tuberculosis. Early clinical diagnosis is difficult and microbiological
\nconfirmation is rare, leading to delayed treatment, resulting in considerable morbidity and mortality. The GeneXpert MTB/RIF
\ntest was evaluated in suspected cases of tuberculosis meningitis.
\nMETHODS
\nA cross-sectional study including all adult patients admitted to the hospital with a suspicion of TBM was carried out. Cerebrospinal
\nfluid study was carried out including biochemical study, cytological study, Gram stain, Ziehl-Nelson (ZN) smear, Microbiological
\nGrowth Indicator Tube (MGIT) culture, GeneXpert MTB/RIF test. The diagnostic efficacy of Gene Xpert MTB was compared with
\nZN smear and MGIT culture.
\nRESULTS
\nOut of a total of 100 patients suspected of TBM during the study period, 40 were classified as having definite TBM, 6 as having
\nprobable TBM, 2 as having possible TBM, and 52 as not having TBM. Out of 48 cases in TBM group, Xpert MTB showed positive
\nresult in 30 cases, whereas ZN stain and MGIT were positive in 14 and 32 cases respectively. Overall, the sensitivity of Xpert
\nMTB was 62.5% compared to clinical diagnosis of TBM (definite, probable, and possible TBM). Specificity was 100%. The
\npositive predictive value (PPV) and negative predictive value (NPV) were 100% and 74.28% respectively.
\nCONCLUSIONS
\nGeneXpert can be a useful diagnostic method in patients of suspected TBM either AFB smear negative or positive, due to its
\nrapidity and simultaneous detection of Rifampicin resistance.