Genital tuberculosis: Comparative study of the diagnostic modalities

Abstract

BACKGROUND:Genital tuberculosis (GTB) is one of the major causes for severe tubal disease leading to infertility. Unlike pulmonary tuberculosis (TB), the clinical diagnosis of GTB is difficult because in the majority of cases the disease is either asymptomatic or has varied clinical presentation. Routine laboratory tests are of little value in the diagnosis. The objective of this study was to compare the modalities of polymerase chain reaction (PCR) technique, acid fast bacilli (AFB) culture and AFB staining.MATERIALS AND METHODS:The women visiting in vitro fertility center during December 2012 and May 2013 were included in this study. A total of 227 aseptically collected endometrial tissue samples were processed. AFB staining, AFB culture and PCR were carried out using standard procedures.RESULT:Out of 227 patients suspected of GTB, 133 were found to be positive either by AFB smear microscopy, culture or PCR. Out of 133 samples, two samples (1.5%) were found to be positive by all three methods, i.e. microscopy, culture and PCR, 11 (4.8%) were found to be positive by both PCR and culture, whereas 126 (86%) samples were found to be positive only by PCR. The PCR has failed to detect seven cases that were positive by conventional culture method.CONCLUSION:Our study showed that the conventional methods of diagnosis like microscopy and culture are less sensitive when compared with PCR. PCR also helped in early diagnosis of infection. However simultaneously, false negative results were an important limitation of this method. PCR negative samples were found to be positive by culture methods. Deoxyribose nucleic acid PCR is not reliable for TB due to false positive or negative result. Thus, we suggest both culture and PCR as important diagnostic methods for detection of GTB.

Insight into the diagnosis and management of subclinical genital tuberculosis in women with infertility

“…Our study showed a very poor correlation between EB DNA-PCR and Koch's culture which is the gold standard for GTB diagnosis. Other authors[ 24 28 29 ] have also reported this and reiterated the need to perform concomitant culture.…”

“…[ 23 ] Shrivastav et al . in 2014[ 24 ] found that PCR-negative samples in endometrial tissue were positive by culture methods and concluded that DNA-PCR done alone is not reliable for TB diagnosis, it should be combined with culture. Even for pulmonary TB where bacterial numbers are high and sample collection is easy, it is suggested that NAATs should be interpreted within the context of the patients' signs and symptoms, and they should always be performed in conjunction with AFB smear and culture.…”

A Study on Diagnostic Evaluation of Two Different Rapid DNA Polymerase Chain Reaction Techniques Namely Gene Xpert Mycobacterium Tuberculosis/Rifampin (MTB/RIF) and Mycoreal Polymerase Chain Reaction in the Diagnosis of Endometrial Tuberculosis Considering Culture as Gold Standard

“…They concluded that PCR was more sensitive compared to the conventional methods of diagnosis like microscopy and culture, however they also said that DNA PCR is not reliable for diagnosis of genital TB due its limitations of false negativity. [ 19 ] There was another study showing similar results which evaluated the sensitivity of PCR. In this study they compared PCR culture and histopathological examination (HPE) in diagnosis of FGTB in 72 patients.…”

Prevalence of Genital Tuberculosis in Infertile Women; a Study from a Tertiary Care Center in North India

“…A comparison of culture and Xpert demonstrated that geneXpert was useful in confirming diagnosis of female genital tuberculosis in clinically suspected cases. 16,17,18…”