Abstract: Objective To evaluate the clinical value of rRNA amplification assay in the detection ofMycobacterium tuberculosis .  Methods 551 sputum specimens from the patients with doubtful tuberculosis and health volunteers were detected using smear microscopy, L-J medium culture, rRNA amplification assay and real-time PCR. L-J culture used as control, the sensitivity, specificity, positive predictive value and negative predictive value of rRNA assay were analyzed. The accordance rate between rRNA assay and real-time PCR was also analyzed.  Results Compared with L-J culture, the sensitivity, specificity, positive predictive value and negative predictive value of rRNA assay were 98.5%, 95.0%，95.0% and 98.5%, respectively. Its sensitivity and specificity had significant difference between smear-positive and smear-negative specimens (P<0.01). Accordance rate between rRNA amplification assay and real-time PCR was 93.8%, which had significant difference between smear-positive and smear-negative specimens (P<0.05).  Conclusion rRNA amplification assay has a higher sensitivity and specitivity, can shorten the detection time. It would be a promising laboratory diagnosis method.

Key words: tuberculosis, pulmonary/diagnosis, Mycobacterium tuberculosis, mucleic acid amplification techniques, sensitivity and speciticity