[DNA amplification using PCR in the diagnosis of tuberculosis].

BACKGROUND

To evaluate the DNA amplification technique of M. tuberculosis with PCR in clinical samples.

METHODS

We have studied 57 clinical samples of 49 patients using PCR and culture in conventional media. We evaluate the final diagnosis of tuberculosis depending upon the bacteriologic results of all available samples.

RESULTS

We reached a 58% sensitivity and 100% specificity. In 9 samples with positive PCR the culture was negative. The samples belonged to 9 patients with tuberculosis (4 with active disease and 5 with past microbiological diagnosis). In 32 samples with negative PCR test, the microorganism was isolated in 9 cases.

SUMMARY

More studies are needed before PCR technique could be recommended for widespread use in the diagnosis of tuberculosis. Its long duration, the equipment needed and the false negative results are among its limitations.