Abstract: Objective Mycobacterium tuberculosis was detected by the method combining polymerase chain reaction(PCR),hybridization,ELISA,so that the founding of the pathogen can be thought as the diagnostic evidence of tuberculosis.Methods The Mycobacterium tuberculosis DNA was amplified by the specific primers labeled with biotin at 5’end,PCR products with biotin were hybridized with target DNA precoated in the microcell,then the hybrid can be detected by strepavidin labeled with HRP,the next process was similar to ELISA.ResultsAmong the 408 samples which may be contain Mycobacterium tuberculosis,the positive rate were 43.6 percent by PCR hybridization method,25.9 percent by culture,6.4 percent by direct microscopy(Ziehl-Neelsen staining)Conclusion PCR hybridization assay was sensitive specific and fast method for the dignosis of extrapulmonary.

Key words: Polymerase chain reaction, Hybridization, ELISA, Extrapulmonary tuberculosis