POLYMERASE CHAIN-REACTION FOR THE DETECTION OF MYCOBACTERIUM-TUBERCULOSIS DNA IN TISSUE AND ASSESSMENT OF ITS UTILITY IN THE DIAGNOSIS OF HEPATIC GRANULOMAS

A polymerase chain reaction (PCR) assay for the rapid identification o f Mycobacterium tuberculosis, based on amplification of the IS6110 ins ertion sequences, was tested in paraffin-embedded tissue from 64 biops y samples with either positive or negative cultures for Mycobacterium tuberculosis. The utility of this PCR assay in the diagnosis of tuberc ulosis among patients with hepatic granulomas (HGs) was then tested by examining 43 liver biopsy samples. They were classified as either hav ing definitive or probable tuberculosis or as being of nontuberculous origin, on the basis of clinical and microbiologic data and on their r esponse to antituberculous treatment. PCR was 100% sensitive in the di agnosis of culture-positive M. tuberculosis infection in the lymph nod e, lung, and liver. The sensitivity of the PCR in the diagnosis of HG of definitive tuberculous origin was 58%, and the specificity was 96%. PCR is a valuable test for the demonstration of mycobacterial DNA in tissues. Although it is not highly sensitive, the DNA amplification me thod may also be more sensitive than culture in the diagnosis of M. tu berculosis-associated HG.