Abstract: Objective  To evaluate the feasibility and security of Liquid-based Peng’s interlayer vessel technique used for diagnosis of tuberculosis in primary level laboratory.  Methods  In two primary level laboratories of Taixing and Jiangyin Center for Disease Control and Prevention, 754 sputum samples from 385 suspect TB patients were tested simultaneously by two methods: sputum smear and acid-fast staining microscopy examination (direct AFB) and Liquid-based Peng’s interlayer vessel technique. According to clinical diagnosis, the positive rates of the two methods for the sputum samples with different traits or collected at different times were compared by Fisher probabilities in 2×2 table. 12 bacterium-positive sputa were treated with different proportion of digestion liquid, different digestion time, and heating or not. Then the digestive sputa were inoculated at Roche medium at  37℃. The security of the liquid-based method was evaluated by preparing the growth of mycobacteria.  Results  The positive rates of Liquid-based Peng’s interlayer vessel technique and the direct AFB were 23.5% (177/754) and 16.8% (127/754) respectively, which had significant difference (χ²=48.02, P=0.000). The positive rates of these two methods in purulent sputa were 47.5% (94/198) and 40.9% (81/198), which had significant differences (P<0.001). The positive rates for the non-purulent sputa (including bloody sputa, mucus sputa and saliva sputa) were 13.5% (26/193) and 4.7% (9/193) (P<0.001). The sputum samples treated with the digestive liquid were not found the growth of Mycobacteria after the culture for 8 weeks.  Conclusion  Liquid-based Peng’s interlayer vessel technique can improve the positive detection rate in suspect TB patients. It is simple, safe, and suitable for the application at primary laboratory for the diagnosis of tuberculosis and convenient for quality control.

Key words: Tuberculosis,pulmonary/diagnosis, Mycobacterium,tuberculosis, Sputum, Bacteriological techniques, Feasibility studies