Polymerase chain reaction in the diagnosis of tuberculosis

OBJECTIVES: To evaluate efficacy of polymerase chain reaction (PCR), using the insertion sequence IS6110 as target for DNA, to detect Mycobacterium tuberculosis in body fluids of children with suspected tuberculosis (TB). SETTING: Hospitalized patients. METHODS: A comparison of PCR on body fluids, Acid Fast Bacilli staining (AFB), mycobacterial culture and clinical features, with special emphasis on central nervous system (CNS) TB was done over 18 month period. A total of 80 children were evaluated, 41 with probable TB disease and 39 controls. Cases were defined by specific clinical criteria. Controls included patients free of clinical TB. PCR was done on the clinical specimens and compared with clinical findings, radiological features, Mantoux (Mx) testing, AFB staining and culture on Lowenstein-Jensen (LJ) medium. RESULTS: Sensitivity of PCR in CSF samples was 100%, in gastric aspirate samples was 20% and in pleural fluid samples was 100%. CONCLUSION: PCR technique may become a valuable diagnostic tool for the diagnosis of tuberculosis in children especially in CNS TB.