Diagnostic performance of GeneXpert in tuberculosis–HIV co–infected patients at Asella Teaching and Referral Hospital, Southeastern Ethiopia: A cross sectional study

BACKGROUND: GeneXpert is a new introduction in the diagnostic modality to fight tuberculosis (TB) among people living with HIV (PLHIV) under the program of intensified TB case finding. This study aimed to evaluate the diagnostic performance of GeneXpert under the program of intensified TB cases finding among PLHIV. METHODS: Cross-sectional study was conducted by recruiting individuals attending an HIV clinic from February 2018 to January 2019. Data on clinical parameters were collected using a standardized tool. Two-morning sputum samples were collected and processed for smear microscopy and GeneXpert. SPSS 21 used for data analysis. Proportion, percentage, and mean with SD were used to describe variables. Univariate and multivariable logistic regressions were used to assess factors associated with the GeneXpert. Values for which the 95% CI interval not includes 1 and for which P<0.05 were considered significant. RESULT: A total of 384 presumptive TB-HIV co-infection cases were included, of which 166 (43%) were diagnosed to have TB. Fifty-four (32.5%) TB cases were smear AFB positive while 79 (47.7%) TB cases were GeneXpert positive. The GeneXpert detection rate was almost two-fold of that of smear microscopy and all smear positive TB cases were detected by GeneXpert. Moreover, GeneXpert was able to detect an additional third of TB confirmed cases among smear AFB negative cases. Advanced stage of the disease, high viral load and presence of anemia were significantly associated with TB. The WHO TB screening tool remained least sensitive with the lowest positive predictive value. CONCLUSION: GeneXpert demonstrated two-fold case detection rate compared to the sputum smear microscopy and additional third TB case detection rate among smear AFB negative cases. Clinical screening tool for evaluation of TB-HIV co-infection showed poor performance in TB case notification.