COMPARATIVE USEFULNESS OF PCR IN THE DETECTION OF MYCOBACTERIUM-TUBERCULOSIS IN DIFFERENT CLINICAL SPECIMENS

The role of the polymerase chain reaction (PCR) in the diagnosis of tu berculosis in clinical practice remains to be defined; most results ha ve been based on sputum samples. This study systematically compared th e relative sensitivity and specificity of a single simplified method f or different clinical samples. A wide range of clinical samples, inclu ding sputum, bronchoalveolar lavage fluid, cerebrospinal fluid, pleura l fluid, gastric aspirate, pus and tissues (troth fresh and paraffin-e mbedded) was tested. This method did not require routine DNA extractio n before PCR, and consisted of an optimised single tube PCR amplificat ion designed with different sets of time and temperature profiles. A t otal of 398 samples from 293 patients was studied. The sensitivity was 100% for all types of specimens, while the specificity ranged from 95 % for sputam to 88% for bronchoalveolar lavage fluid and pleural fluid and to 85% for non-pulmonary specimens. This study showed that it was possible to employ a single simplified method with minor modification s for a wide range of specimens in clinical practice without loss of s ensitivity and specificity.