Abstract: Objective To evaluate different case finding strategies of MDR-TB, and to provide evidence for developing case finding strategy appropriately. Methods According to geographic and economic conditions, Tianjin, Wanzhou, Puyang, Quzhou and Daqing were selected as study areas. The sputum specimens of smear positive pulmonary tuberculosis(PTB) cases in Tianjin, Daqing and Puyang were sent to prefecture lab for culture and drug susceptibility test (DST) (Model 1), those in Quzhou and 6 counties (districts) were cultured in the lab at county level, and the positive cultural substance were sent to prefecture lab for DST (Model 2). 7733 cases of smear positive PTB in 5 areas and all 3427 cases of smear negative patients in Tianjin registered from March 2010 to February 2013 were screened with sputum culture and DST (isoniazid, rifampicin, streptomycin, ethambutol, ofloxacin and kanamycin). Delay of diagnosis, MDR-TB and XDR-TB detection rate were collected and analysed by descriptive method and Chi square test by SPSS 13.0. Results Specimen examination rates of Model 1 and 2 were 76.5% (3078/4026) and 90.4% (2017/2232) respectively, and the difference had statistical significance (χ²=183.7, P<0.05). The culture positive rate of Model 1 and 2 were 89.9% (2455/2730) and 87.2% (2232/2559) respectively, there was no statistical significance (χ²=0.2234, P>0.05). The median of MDR diagnosis delay by traditional DST was 104 (86, 138) d, some even longer than 1 year. The detection rates from the highest to lowest were retreatment (17.1%, 129/755), new smear positive (2.1%, 97/4534) and smear negative (0.5%, 9/1937). Conclusion Depending on the resources of different settings, either culture and DST by prefectural-level model or culture by county-level and DST by prefectural-level model are reasonable. Because traditional DST takes longer period, rapid molecular test for drug resistance is recommended for developed setting. Selecting smear positive patient as the scree-ning objects covers majority of MDR-TB patients, screening MDR-TB among smear negative is recommended for developed setting.

Key words: Tuberculosis, pulmonary, Drug resistance, multiple, bacterial, Microbial sensitivity tests