Evaluation of Microscopy, Culture and PCR Methods in the Laboratory Diagnosis of Genito-urinary Tuberculosis

摘要

Genitourinary tuberculosis (GUTB) is the second most common form of extrapulmonary tuberculosis, with more than 90% of cases occurring in developing countries. In GUTB, the kidneys are the most common sites of infection and are infected through hematogenous spread of the bacilli, which then spread through the renal and genital tract. Diagnosis of TB is often delayed owing to the nonspecific nature of its presentation; therefore, a high degree of suspicion should be exercised and a systematic approach should be taken during investigation. The aim of this study was to apply bleach concentration method for detection of AFB in 5-day morning urine samples obtained from the suspects of urinary tuberculosis and to correlate the results with conventional Zeihl Neelsen (ZN) staining, TB culture and TB-PCR. A total of 46 samples were studied from clinically suspected cases of urinary tuberculosis. All the samples were processed for conventional ZN staining, Bleach concentration followed by ZN staining, TB culture on LJ media and TB-PCR (IS 6110) by standard protocols. Out of the 46 samples evaluated all were negative (0%) by conventional ZN staining, while the positivity increased to 7(15.22%) by bleach concentration method, the gold standard i.e. TB culture had 9(19.56%)?positive and the?TB-PCR gave 4(8.69%) positive. The results revealed that bleach concentration method was superior to conventional ZN staining method and TB-PCR. Though TB culture was found to be the best method, but it takes a long time for the diagnosis.