OBJECTIVE: For rapid detection of Mycobacterium tuberculosis existence in the genitourinary tract a polymerase chain reaction (PCR) was established to examine urine bacteria.MATERIALS AND METHODS: By using 3 DNA primers (MPB, INS, and Pt) and the PCR method, totally 50 specimens of urine (12 cases of definitive TB, 19 cases of suspicious TB, and 19 cases of ordinary UTI), 2 specimens of local discharge, and 3 specimens of resected tissues were analyzed.RESULTS: The positive detection rates of the 3 DNA primers, MPB, INS, and Pt, in definitive TB patients (true-positive rate) were 88.3%, 75.0%, and 41.7%; in suspicious TB patients (diagnostic rate) were 31.6%, 42.1%, and 26.3%; and in UTI patients (false-positive rate) were 15.8%, 36.8%, and 10.5%. MBP-nested PCR had the highest diagnostic power for TB infection in urine with an acceptable false-positive rate. The INS probe is not suitable for detection because both its high true- and false-positive rate were high, while the Pt probe had the lowest false-positve rate but also a low true- positive rate. Only 1 out of 17 cases (11.8%) showed a positive smear examination and TB culture, respectively. Interestingly, 4 patients after anti-TB triple therapy still had a positive PCR reaction in their urine.CONCLUSIONS: These results provide us with an early diagnosis of M. tuberculosis infection in the genitourinary tract which can improve the treatment outcome of patients by using MPB-nested PCR. However, more-sensitive primers should be developed in the future for increasing the diagnostic rate.