Abstract: To analyze out-of-control reasons of clinical biochemical internal quality control from January 2009 to December 2013 in Department of Clinical Laboratory, Inner Mongolia Forestry General Hospital, to summarize the corrective and preventive measures, and to reduce out-of-control rate gradually. According to the reference of Westgard quality control rules, the out-of-control results of daily internal quality control by OLYMPUS AU5421/AU640 automatic biochemical analyzer and original reagents, control materials and calibrators were analyzed retrospectively for 5 years. In terms of calibrators, reagents, human factors, control materials, instruments and other factors, the statistical analysis about out-of-control reasons was performed. For 5 years, there were 242 out-of-control cases, including 69 calibration problems, 54 reagent problems, 50 control material problems, 31 human factor problems, 23 instrument problem and 15 other problems. Calibration, reagent, control material reasons accounted for more than 70% of all reasons, and compared with human factor, instrument and other reasons, there was statistical significance(P<0.05). Calibrators, reagents, human factors, control materials and instruments are the main reasons causing out-of-control situations. Clinical laboratories should take effective measures, regulate the standard operating procedure, strictly control the quality of biochemical determination and persist in improving the quality of clinical inspection.

Key words: Biochemical determination, Internal quality control, Out-of-control reason