Portal de Periódicos da CAPES

Clinical utility of the Gen-Probe amplified Mycobacterium tuberculosis direct test compared with smear and culture for the diagnosis of pulmonary tuberculosis

1998; Elsevier BV; Volume: 4; Issue: 8 Linguagem: Inglês

10.1111/j.1469-0691.1998.tb00392.x

1469-0691

Claudio Piersimoni, Piergiorgio Zitti, Maria Enrica Cimarelli, Domenico Nista, Giuseppina De Sio,

Diagnosis and treatment of tuberculosis

ObjectiveTo evaluate the clinical efficacy of the Gen-Probe amplified Mycobacterium tuberculosis direct test (AMTD), a recently developed amplification test for the detection of M. tuberculosis complex directly from clinical specimens, for the diagnosis of pulmonary tuberculosis and its suitability for use in a routine microbiology laboratory.MethodsSequential respiratory specimens were tested with AMTD and results were compared with those of acid-fast stain and culture. Performance of AMTD was tested over a 13-month period, using 278 respiratory specimens, from 219 patients, submitted to the microbiology laboratory of our hospital. AMTD's sensitivity, specificity and positive and negative predictive values were determined, with the combination of culture and clinical diagnosis being taken as the standard.ResultsThirty-three specimens were collected from 23 patients with a conclusive diagnosis of pulmonary tuberculosis. Of these specimens, 13 were smear positive, 22 culture positive and 30 AMTD positive. AMTD was more sensitive in detecting pulmonary tuberculosis in patients partially treated but with undiagnosed disease (100%), and in smear-positive disease (100%). The overall sensitivities, specificities and positive and negative predictive values were: 39.4%, 100%, 100%, and 92.4% for staining; 66.7%, 100%, 100% and 95.7% for culture; and 90.9%, 100%, 100%, and 98.8% for AMTD.ConclusionsAMTD is a rapid, reliable and accurate test for the detection of M. tuberculosis complex in respiratory specimens. Repeat testing of those samples whose results fall between 30 000 and 300 000 relative light units, increases test specificity by preventing the majority of false positives. To evaluate the clinical efficacy of the Gen-Probe amplified Mycobacterium tuberculosis direct test (AMTD), a recently developed amplification test for the detection of M. tuberculosis complex directly from clinical specimens, for the diagnosis of pulmonary tuberculosis and its suitability for use in a routine microbiology laboratory. Sequential respiratory specimens were tested with AMTD and results were compared with those of acid-fast stain and culture. Performance of AMTD was tested over a 13-month period, using 278 respiratory specimens, from 219 patients, submitted to the microbiology laboratory of our hospital. AMTD's sensitivity, specificity and positive and negative predictive values were determined, with the combination of culture and clinical diagnosis being taken as the standard. Thirty-three specimens were collected from 23 patients with a conclusive diagnosis of pulmonary tuberculosis. Of these specimens, 13 were smear positive, 22 culture positive and 30 AMTD positive. AMTD was more sensitive in detecting pulmonary tuberculosis in patients partially treated but with undiagnosed disease (100%), and in smear-positive disease (100%). The overall sensitivities, specificities and positive and negative predictive values were: 39.4%, 100%, 100%, and 92.4% for staining; 66.7%, 100%, 100% and 95.7% for culture; and 90.9%, 100%, 100%, and 98.8% for AMTD. AMTD is a rapid, reliable and accurate test for the detection of M. tuberculosis complex in respiratory specimens. Repeat testing of those samples whose results fall between 30 000 and 300 000 relative light units, increases test specificity by preventing the majority of false positives.