Background: Diagnosis of extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed prospectively the performance of Real Time PCR in diagnosing smear-negative tuberculosis (TB), which represents the most common form of TB in a low incidence setting.

Methods: The present study was undertaken to find the effectiveness of Polymerase Chain Reaction targetting IS6110, MPB64 and 16SrRNA genes and culture on L–J media in Ziehl-Neelsen stain negative samples of body fluids for rapid diagnosis of suspected cases of Extra pulmonary tuberculosis.

Results: A total of 62 samples were taken of which 2 samples were not adequate in amount and hence were excluded. All 6 (10%) culture positive samples were PCR positive, in addition PCR could detect 5 out of 60 (8.3%) samples to be positive which were negative by culture. Of the 11 positive samples only MTB was reported by PCR and No NTM was detected.

Conclusions: PCR is a sensitive method for rapid diagnosis of TB compared to the conventional ZN staining. PCR can serve as a sensitive diagnostic method for microbiological diagnosis of smear-negative TB in countries with a low TB prevalence.

Keywords: extra-pulmoary, smear negative tuberculosis, sputum smear negative, tuberculosis

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Dr Varun Goel

Department of Microbiology, Santosh Medical College & Hospital, Ghaziabad, UP., India