Abstract: Objective  To study the performance of indicating the growth of Mycobacterium tuberculosis complex (MTBC) by culture filtrate MPT64 antigen detection method.   Methods  799 BACTEC MGIT 960 mycobacterial cultures at 42 days and 1265 cultures every 7 days until the occurrence of a positive test result or the forty-second days were detected by MPT64 antigen detection method. Compared with BACTEC MGIT 960 mycobacterial culture system, the accuracy and rapidity of MPT64 antigen detection method were analyzed in 2064 BACTEC MGIT 960 cultures.   Results   (1) Of 2064 clinical samples, 298 MTBC strains, 108 non-tuberculous mycobacteria (NTM) strains, 1521 culture-negative cases and 137 cases of pollution were reported respectively by BACTEC MGIT 960 mycobacterial culture system, in which 279, 6, 0 and 2 samples were MPT64-positive respectively. The overall consistency of two methods was 98.69%（2037/2064）, The positive rate of MPT64 antigen detection method was 93.62%（279/298）in BACTEC-positive cultures. (2) Of 1265 cultures, 168 were identified as MTBC by these two methods. For these 168 samples, the positive rates of MTBC at 1 to 6 weeks were 25.60% (43/168), 66.67% (112/168), 92.26% (155/168), 98.21% (165/168), 98.81% (166/168) and 100.00% (168/168) respectively by BACTEC MGIT 960 mycobacterial culture system, while 17.26% (29/168), 61.90% (104/168), 89.88% (151/168), 95.24% (160/168), 98.81% (166/168) and 100.00% (168/168) respectively by culture filtrate MPT64 antigen detection method. The times of positive reports had not significant difference between two methods（t=1.68，P=0.366）.   Conclusion  The culture filtrate MPT64 antigen detection method to indicate growth of MTBC is accurate, fast, easy to operate and worthy of promotion in the clinical application. Especially, it is very suitable to primary hospitals without specific equipment and reagent.

Key words: Mycobacterium tuberculosis, Antigens,bacterial, Bacterial proteins, Bacteriological techniques