PCR in tuberculosis: An extremely useful tool?

Introduction: Tuberculosis is a global air borne infectious disease with significant increase in incidence and prevalence. Conventional methods take longer time for diagnosis and drug susceptibility with less sensitivity and specificity. So rapid diagnosis and detection of multi, extensive and total drug resistant bacilli are of up most importance for therapeutic purpose. Materials and Methods: It was a retrospective study in tertiary care. All clinical samples suspected for tuberculosis received by laboratory were included in the study. The samples were processed for microscopy by ZN stain, culture by LJ media and RT-PCR. Results: Total 566 sample were tested out of 177 (31%) were positive for tuberculosis. 62% samples were PCR positive, 51% were culture positive and 49% were smear positive. The most common sample received with maximum positivity rate was pleural fluid (34%). Male predominance was seen with young adults as the predominant group affected. Conclusion: The present study shows good specificity of PCR with sensitivity of 50%. It detects 50% times more cases in relation to conventional results where they fail to produce correct results. More such comparative studies are needed to establish importance of PCR in early diagnosis and treatment.