Accuracy of urinary PCR as compared with urine culture for early diagnosis of genitourinary tuberculosis

Aim: to determine the sensitivity and specificity of pcr in early diagnosis of genitourinary tuberculosis when compared with urine culture for detection of genitourinary tuberculosis. methods: this observational cross-section study was conducted from december 2011 to may 2012 at shaikh zayed hospital,lahore in the in the department of urology it is a prospective study of 50 patients to evaluate various modes of presentation of genitourinary tuberculosis and efficacy of various diagnostic tests currently available. results: the patients age range from 20-67 (38.23±13.27 years). male to female ratio was 1:1.16. nineteen patients (100%) had growth of mycobacterium tuberculosis on routine culture on lowenstein jensen (lj) medium (gold standard) and were considered positive for tuberculosis. thirteen patients showed acid fast bacilli in their urine on zn staining (sensitivity 51.5%,specificity 94.6%). eighteen (18) patients showed acid fast bacilli in their urine on pcr,out of which 16 patients showed growth on lj medium with a sensitivity of 88.6% and specificity of 96.5% (positive predictive value 95.3% and negative predictive value 92.4%). conclusion: genitourinary tuberculosis remains the most common form of extrapulmonary tuberculosis. polymerase chain reaction (pcr) is a very sensitive,specific and rapid diagnostic test and the only disadvantage is that it can not differentiate between the live and dead bacteria.