Assessment of the diagnostic value of PCR method in detection of the mycobacterium tuberculosis in urine samples

ABSTRACT

Despite health improvement, the incidence of tuberculosis has increased during recent years. In this study, the diagnostic value of PCR method was evaluated in the detection of mycobacterium tuberculosis in urine samples. In this diagnostic test study, we evaluated all urine samples gathered from inpatients and outpatients visited in Massih Daneshvari hospital between 1999 and 2005. PCR results were compared to the findings of direct smear and culture of urine samples. Totally, 509 urine samples were studied. In 2 samples, every three tests [culture, bacterioscopy and PCR] were positive; in 5 samples bacterioscopy was positive, but PCR was negative. In 19 samples, PCR was the only positive test. In 471 samples every three tests were negative. Sensitivity, specificity, positive predictive value and negative predictive value of PCR method in detecting of mycobacterium tuberculosis in urine sample was 31%, 96%, 31% and 96%, respectively. As sensitivity of PCR test is low, it is not considered to be a useful method for detecting mycobacterium tuberculosis in urine, but according to high specificity, it can be used for identifying healthy people and following up patients' response to treatment