USE OF POLYMERASE CHAIN-REACTION FOR IMPROVED DIAGNOSIS OF TUBERCULOSIS IN CHILDREN

Objective: To study the value of a rapid diagnostic method based on th e amplification by polymerase chain reaction (PCR) of a fragment of th e IS6110 insertion element for the detection of Mycobacterium tubercul osis in children. Design: We tested 199 specimens obtained from 68 chi ldren referred for evaluation of suspected tuberculosis. Results: In 8 3.3% of children with active disease and 38.9% with tuberculous infect ion but no evidence of disease, at least one positive PCR result was o bserved. No child without tuberculosis had positive PCR results (100% specificity), The sensitivity of the PCR was increased by testing of m ultiple samples from the same child and use of Chelex particles (Bio-R ad Laboratories, Ivry, France) rather than guanidine isothiocyanate-si lica particles for DNA extraction, Bronchoalveolar lavage samples were no more useful than gastric aspirates. Conclusions: If appropriate la boratory methods are used, DNA amplification is a reliable method for the early diagnosis of tuberculosis in children and appears to be very helpful in clinical pediatric practice when the diagnosis of active t uberculosis is difficult or needs to be rapidly confirmed.