Comparision of the conventional diagnostic techniques,BACTEC and PCR.

ABSTRACT

Two hundred and thirty samples from suspected pulmonary and extra pulmonary cases of tuberculosis were processed for detection of Mycobacterium tuberculosis by ZN smear examination, LJ medium culture, BACTEC radiometric culture and Polymerase Chain Reaction tests. A significant difference was seen in the sensitivities of different tests,ie.73.9% for PCR tests,34.78% for ZN smear examination, 52.17% for LJ culture and 58.69% for BACTEC culture. However,there was no significant difference in specificity of different tests(P> 0.05). PCR test sensitivity in pulmonary and extrapulmonary clinical samples was 74.0% and 78.5% respectively and found to be significantly higher (P<0.05) when compared with those of other tests. The mean detection time for M.tuberculosis was 24.03 days by LJ medium culture, 12.89 days by BACTEC culture and less than one day by PCR test.