An evaluation of Composite Reference Standard (CRS) for diagnosis of Female Genital Tuberculosis

Female genital tuberculosis (FGTB) is a common cause of infertility in developing countries. Its diagnosis is difficult due to its paucibacillary nature, with no single test having high sensitivity and specificity. This study is to share the experience of using Composite Reference Standard (CRS) for the diagnosis of FGTB.

This is a prospective study conducted between September 2017 to June 2019, over 100 infertile females found to have FGTB on composite reference standard which consisted of acid-fast bacilli on microscopy or culture, histopathological evidence of epithelioid granuloma, positive gene Xpert on endometrial sample or definite or probable finding of FGTB on laparoscopy.

A total of 100 infertile women (78% primary, 22% secondary) found to have FGTB on CRS were enrolled in this study. Mean age, body mass index, parity and duration of infertility were 28.2 years, 23.17 kg/m², 0.24 ± 0.12 and 2.41 years respectively. Various symptoms were scanty menses (16%), irregular cycle (7%), dysmenorrhea (11%), pelvic pain (11%). Various signs were vaginal discharge (65%), adnexal mass (6%), tubo-ovarian mass on ultrasound (15%), abnormal hysterosalpingography findings (57.14%), positive polymerase chain reaction test (65%) and abnormal hysteroscopy (82.2%). The positive findings on CRS were positive AFB on microscopy or culture (3%), positive gene Xpert (28%) (done in some cases), epithelioid granuloma on histopathology (13%), definite findings on laparoscopy like tubercles, caseous nodules and beaded tubes in (57.19%) patients while probable findings of FGTB like straw colored fluid in POD, extensive dense pelvic, peri-tubal, peri-ovarian adhesions; hydrosalpinx; tubo-ovarian mass; thick fibrosed tubes; mid tubal block; peri hepatic adhesions (Fitz Hugh Curtis Syndrome); hyperemia of tubes/blue uterus on chromotubation were seen in (48.8%) patients. All patients found to be positive on CRS were given 6 months of anti-tubercular therapy.

This study demonstrates the high reliability of use of composite reference standard for diagnosis of FGTB.