Cartridge-based nucleic amplification (CBNAAT)/GeneXpert test as a diagnostic modality for the detection of genital tuberculosis in women with infertility.

BACKGROUND

Genital tuberculosis (GTB) is a significant etiological factor of infertility in developing countries such as India; however, it is frequently undiagnosed due to its asymptomatic nature and a lack of standardised protocols. This study aimed to compare the diagnostic efficacy of GeneXpert (CBNAAT) with Ziehl-Neelsen (ZN) staining, Mycobacterial Growth Indicator Tube (MGIT) liquid culture and histopathological examination (HPE). Additionally, the occurrence of GTB in infertile women aged between 18 and 45 years was also determined.

METHODS

The study comprised 200 infertile women with suspected GTB. Endometrial biopsy samples were collected aseptically and subjected to ZN staining, MGIT liquid culture, GeneXpert testing and HPE and the results were analysed and compared. MGIT was considered the gold standard test in accordance with National TB Elimination Programme (NTEP) recommendations.

RESULTS

There were 164 (82%) cases of primary infertility, and 36 (18%) cases of secondary infertility. Out of the 200 samples of endometrial biopsy (EB) specimens, the GeneXpert test detected two positive findings (1%), ZN staining detected two positive results (1%), and MGIT liquid culture as well as HPE detected one positive result (0.5%). GeneXpert demonstrated a sensitivity of 100% (confidence interval (CI) 2.50-100.00%), a specificity of 99.5% (CI 97.23-99.99%), a positive predictive value (PPV) of 50% (CI 12.40-87.60%), and a negative predictive value (NPV) of 100% (CI 98.15-100.00%), with liquid culture as reference. A significant agreement was found between the diagnostic procedures of MGIT and GeneXpert, with a kappa value of 0.66 and a p-value of 0.047 (significant p-value <0.05).

CONCLUSION

The present study is among the few that has utilised GeneXpert to aid in the diagnosis of female genital tuberculosis (FGTB). GeneXpert, being much faster and more feasible than conventional methods such as culture, could be incorporated into the standard evaluation of GTB.