Objective To investigate the current situation of precision of internal quality control (IQC) in total cholesterol,triglyceride,HDL-cholesterol,and LDL-cholesterol and provide improvement measurements.Methods Web-based External Quality Assessment (EQA) system was used to collect IQCdata of lipid tests from 581 EQA participant laboratories nationwide.The data include the coefficient of variation (CVs) of IQC data under control in April 201 1 and long-term cumulative data.Excel 2007 was applied for data processing after excluding the invalid data.Acceptable rates of CVs of two-lot internal quality controls in 4 lipid testing were calculated according to 6 criteria,that were 1/4TEa,1/3TEa,allowable imprecision of National Cholesterol Education Program (NCEP) and the specifications based on biological variation including the optimal,appropriate and minimal allowable imprecision.Results Four hundred and thirty-five,434,405 and 360 laboratories reported the data of level 1 IQC for total cholesterol (TC),triglyceride (TG),HDL-C,LDL-C respectively,while 214,214,192 and 171 reported the data of level 2 IQC respectively.Acceptable rates of TC,TG,HDL-C,LDL-C based on NECP criteria were 69.2％ (304/435),85.3％ (370/434),61.3％ (48/405) and 69.0％ (248/360) for level 1 respectively while 81.3％(174/214),91.6％ (196/214),75.5％ (145/192) and 81.3％ (139/171) for level 2 respectively.In the group which met the NECP criteria,the proportion of using matching detection system was much higher than the group which did not meet the criteria.Conclusions It is an effective way for clinical laboratories to improve test quality by monitoring the current and cumulative CVs of internal quality control and comparing them against proper evaluation criteria to evaluate if the analysis system can meet quality requirements.

ObjectiveTo describe upper and lower limits and their sources of reference intervals in routine chemistry assays and to make a comparison between routine and dry chemistry in these aspects.MethodsThe data of reference intervals were collected,which come from the third run of 2010 External Quality Assessment (EQA) programs in routine and dry chemistry performed by National Center for Clinical Laboratories(NCCL).All data from maternal and child care service center,children's hospital and corporations were excluded.Then all the abnormal values and errors (for instance,the lower limit was higher than the upper one or the upper limit was as the same as the lower one,etc.) were eliminated,either.Data statistics was performed by SPSS 13.0 referring to upper and lower limits of reference intervals and sources of 24 routine chemistry assays ( including serum potassium and serum sodium,etc).Comparison was made between routine and dry chemistry in these aspects in 23 assays.Data from adult men were reported when gender difference was present.ResultsThe three main sources of reference intervals were National Guide to Clinical LaboratoryProcedures, instructions of reagent manufacturesanddetermined by their own laboratory.In comparison of reference intervals between routine and dry chemistry,6 assays had statistical significant difference in both upper limits and lower ones while,4 assays in one-sided limits and 13 assays were not statistically significant in both limits.Conclusions The reference intervals of routine chemistry have big differences among institutions and the sources of them are various.Only a few assays have statistical significant difference in routine and dry chemistry among medical institutions,it might be discussed in further study whether the statistical results have clinical values.In order to achieve the result agreement among clinical assays,all the laboratories must share the common reference intervals on the basis of standardization.