Abstract: Objective: To investigate the trueness and precision of routine clinical biochemistry tests in the third-grade class-A hospitals of Chongqing city. Methods: The fresh frozen serum samples were assigned the target values with reference methods, and then allocated to the clinical laboratories of the third-grade class-A hospitals in Chongqing city for testing. The trueness and precision were analyzed and evaluated. Results: The pass rates of trueness of creatinine (Cr), total protein (TP), total bilirubin (T-Bil), uric acid (UA) and glucose (Glu) in 33 clinical laboratories were below 50%. The pass rate of trueness of UA (33%) in the closed detection system was lower than that in the opening detection system (79%, P=0.033). In the opening detection system, the pass rate of trueness of Cr in the mode with the same brand of reagents and calibration materials was higher than that with different brands (P=0.014). The precisions of level 1 of T-Bil and Urea in the closed detection system were better than that in the opening detection system (P=0.043 for T-Bil; P=0.031 for Urea). Conclusion: The trueness of clinical biochemistry tests in the third-grade class-A hospitals of Chongqing city needs to be further improved. There is no significant difference in trueness and precision between the opening detection system and the closed detection system, even the performance of some tests in the opening detection system is better than that in the closed detection system.