To investigate the levels of carbohydrate antigen 19-9 in the urine samples of the patients with bladder cancer and to evaluate its clinical diapnostic value. Urine samples were taken from 30 patients with bladder cancer

53 with benign

22 with malignant urological diseases and 35 with malignant tumors from other systems

together with 30 normal subjects which have no any history of cancers or other urological diseases. CA19-9 was assayed by Chiron Diagnostic Corporation ACS:180SE. The CA19-9 level of the group with bladder cancer was 159.0±128.0U/mL

while that of the group of control was 12.4±8.4U/mL. The critical points were determined as the mean value of the group of control ±1.96 SD

then >28.9U/mL was considered as positive. The diagnostic sensitivity for bladder TCC were 86.7% and specificity were 68.2%. CA19-9 level in the bladder cancer group was significantly different from that of control group ( P <0.001)

and also different from those of other groups. The urine CA19-9 level in the group of benign urological diseases was 53.9±77.9%

significantly higher than that of control ( P =0.001)

but not significantly different from those of the group of other urological cancers and other systems cancers. Preliminary study indicates that CA19-9 urine samples study is a non-invasive auxiliary index for the clinical diagnosis of bladder cancer. The method is simple and useful. But the interference from other benign and malignant diseases as well as gene-types should be considered in clinical practice.