Comparison of the Efficacy of the Cartridge-Based Nucleic Amplification (CBNAAT)/Xpert Test and Histology of Genital Tissues in Diagnosing Female Genital Tuberculosis

Abstract

BackgroundDiagnosing female genital tuberculosis (FGTB) is very difficult by routine laboratory investigations. Collecting tissues from genital structures, especially from tubes for histology, is impossible. The cartridgebased nucleic amplification (CBNAAT)/Xpert RIF test is a new polymerase chain reaction (PCR)-based method that is quick and may diagnose FGTB from any tissue type; however, it should not be contaminated with blood. This study was conducted to compare the efficacy of CBNAAT and the histology of genital tissue in suspected cases. Materials and methodsThis was a prospective study of the diagnostic efficacy of 91 cases of suspected FGTB randomly selected from March 2018 to September 2019 at a rural tertiary care center. Endometrial tissue collected in 86 patients (59 infertility, 27 menstrual irregularities) and tubal/peritoneal tissue from hysterectomy or laparotomy specimens of five participants who underwent surgery were sent for histopathological analysis and CBNAAT and the results were evaluated and compared. ResultsThere were 59 (64.83%) and 32 (35.2%) cases of infertility and menstrual irregularities, respectively. Primary infertility (38; 41.75%) was the most common complaint. Endometrial biopsies (EB) of two (2.23%) cases were found positive for tuberculosis (TB) both on histopathological examination (HPE) and CBNAAT. In addition, both patients had primary infertility. Of the 32 cases with menstrual abnormalities (27 EB and three tubal tissue, two peritoneal and nodular tissue), none were found to be positive for TB on HPE or CBNAAT. A highly significant association was found between histopathology and CBNAAT (p<0.0001) in the endometrial tissue of infertile patients. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100% for CBNAAT, with reference to histopathology. ConclusionWe recommend CBNAAT for the early detection of FGTB, with the added advantage of early results, minimal technical expertise, and detection of drug-resistant tuberculosis (TB).

Evaluation of culture, molecular assay (TB-PCR), GeneXpert system and histopathology for detection of genital tuberculosis

“…Investigation named GeneXpert assay was considered as gold standard to diagnose of genital TB. 16,17 2.1. The following investigations were used as an instrument in our study BACTEC Culture: BACTEC culture was a radiometric culture and released carbon dioxide by bacteria was measured.…”

“…GeneXpert System or GeneXpert assay is a cartridge based nucleic acid amplification test (CBNAAT): It uses heminested real time PCR to amplify and simultaneously detect Mycobacterium tuberculosis complex (MTBC) and resistance to rifampin (RIF) within 100 minitues. 17 Due to constraints of our study objectives, we had not collected data for drug resistance.…”