Glycated hemoglobin plays an important role in diabetes management.International standardization of HbA1c initiated 20 years ago and has been performed successfully.The standardization of HbA1c in China has been started several years 3 labs have become approved laboratories of IFCC reference network.Reference methods were applied to transfer trueness in the national trueness verification project.The measurement performance of HbA1c testing have improved in recent years and the between-lab CVs reduced evidently.All participants will continue efforts to improve HbA1c testing to fulfill the clinical needs.

Objective To investigate the stability of glycated hemoglobin HbA1c in whole blood sample measured by Tosoh G7, Roche/Hitachi 7170A and NycoCard READER Ⅱ under different storage conditions. Methods Three whole blood samples (EDTA anticoagulated) with different glycated hemoglobin levels and one whole blood sample (heparin anticoagulated) were collected and stored at -80 ℃, -20 ℃, 4 ℃,room temperature(15 -25 ℃), and 37 ℃ HbA1c was analyzed by each method on days 1, 2, 5, 7, 9, 14, 21,28, 35, 42, 49, 56, 63 and 70 respectively. Results The results of sample stored at -80 ℃ appear to be stable for Tesoh G7 and Roche/Hitachi 7170A method. The coefficients of variation (CV) for Tosoh G7 was 0.54%-1.22%. The CV for Roche/Hitachi 7170A was 0.86% -1.82%. When samples was detected with Tosoh G7 method, the results was consistent when the sample was stored at -20 ℃ for 14 days, 4 ℃ for 63 days, room temperature for 5 days, and 37 ℃ for less than 1 day. When samples was detected with Roche/Hitachi 7170A method, the results was consistent when the samples was stored at -20 ℃ for 21 days, 4 ℃ for 42 days, room temperature for 7 days, and 37 ℃ for less than 1 day. The NycoCard READER Ⅱ showed stability at 4 ℃ for 9 days, and room temperature for less than 1 days. Conclusions The stability of whole blood samples is dependent on different methods. Storage time under different temperatures is different.

Isotope dilution mass spectrometry is a reliable principle for small molecule analyte measurements.It is a precise,accurate method with very high specificity,which is very suitable for lowconcentration steroid hormones tests.The published reference methods are all based on this principle so far.In this paper,the applications of isotope dilution mass spectrometry in the determination of steroid hormones were reviewed.

Objective To investigate the results of different measuring procedures of hemoglobin A1c (HbA1c) trueness verification scheme in China.Methods Cross sectional survey.The data were collected via the External Quality Assessment (EQA) software from laboratories participated in the First HbA1c trueness verification EQA.Then the collected data were divided into several groups based on laboratory instruments and the data from less than 5 group were excluded.The observed imprecision, bias and sigma (σ) were calculated and the bias％ and CV％ were drew in the sigma chart.The average bias％, CV％ and weighted average σ of each level were also calculated.Results Total 123 laboratories were divided into 9 groups and setting 6％ as the Allowable Total Error, the average bias％, CV％ and weighted average σ of 201411 (target value was 5.4％) were 3.70％, 4.55％ and 0.51 respectively σ, of 201412 (target value was 7.8％)were 2.42％ , 3.56％ and 1.24σ respectively.None of the group achieved the 2σ quality of 201411, and 1 group achieved the 2σ quality of 201412.Conclusions There are obvious biases among the results of many measuring systems and the target value assigned by reference measuring procedures of HbA1c, as well as the imprecision.The Sigma External Quality Assessment Chart is a visual tool, indicating that the quality of measuring systems necessitate improvement therefore to ensure the reliability of results and make better use of HbA1c in clinical application.

Objective To research on a whole blood control material for lymphocyte subset counting by flow cytometry(FCM).Methods To detect lymphocyte subset in whole blood with different preservers by flow cytometric multi-color analysis.Results whole blood control material for lymphocyte subset counting by FCM was prepared.In 2-8℃ refrigerator, the light scatter and CD45 of leukocytes of whole blood control were stable in 72 days. The cluster of lymphocyte, monocyte, neutrophil in plot were separated easily from debris. The lymphocyte subset of whole blood control can be counted by FSC/SSC or CD45/SSC gating. The variation of lymphocyte subset count was less in different preserving day. The coefficient of variation (CV) of lymphocyte subset count was less than 6.5% in our laboratory and less than 13% in external quality assessment among 56 laboratories in China.Conclusion The whole blood control prepared by us can be used for internal quality control and external quality assessment in lymphocyte subset counting by FCM, it is very important signification to ensure the quality and accuracy of lymphocyte subset count.

This article summarized recent correlative literatures focusing on international standards on glycated hemoglobin.The basic concept,determination of glycated hemoglobin,the present review in laboratory measurement and metrological traceability was introduced.The international community has established reference system and metrological traceability to the International System of Units on HbA1c.Determination in glycated hemoglobin is still in incipient stage in our country.Both clinical laboratorians awareness and clinical determination need to be strengthened.

Objective To investigate preanalytical and intraindividual biological variations of 19 biochemistry analytes. Methods For the study of preanalytical variations, 10 consecutive blood specimens were taken from each of 21 individuals and the specimens were taken from different arms and with various evacuated blood tubes and venous occlusion durations and processed with different storages before and after centrifugal separation of serum. Another 3 aliquots of blood, each at an interval of 1 week, were taken from the individuals for the study of intraindividual biological variations. All the serum samples were analyzed in duplicate for 19 biochemistry analytes. Analysis of variance was performed on the results for the estimation of preanalytical and biological variations. Results Various preanalytical treatments or factors caused some systematic variations but random specimen errors were the main contributors of preanalytical variations. Chloride, sodium and calcium showed preanalytical variations of less than 1% and other analytes ranging from 1%-7%. Different analytes showed varied intraindividual biological variations. The least biological variations ( <2% ) were observed on chloride, sodium and calcium and the largest ( >20% ) on bilirubin,triglycerides, alanine aminotransferase and creafine kinase. Conclusions Preanalytical variations under laboratory settings in China and intraindividual biological variations in Chinese for 19 biochemistry analytes have been estimated. These data will be useful in the estimation of measurement uncertainty and the interpretation of clinical laboratory results.

Objective To verify the trueness and assess the traceability of results from a routine chemistry system procedure for measurement of urea and ereatinine in serun.Methods Series of fresh frozen patieot sera,whose values of urea or creatinine were assigned by isotope dilution gas chromatography mass spectrometry (ID-GC/MS) or isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS),were chosen to be analyzed by a routine chemistry system.The measurement results of urea and creatinine by the routine chemistry system were used for linear regression analysis against the assigned values bv the ID-MS method to calculate the percentage deviation and assess the expected bias.Results For urea and creatinine,the linear regression equations between the routine chemistry system and ID-MS methods were Y =0.9890X + 0.0192 (R2 =0.9990) and Y =0.9815X-6.4794 (R2 =0.9989),and the average percentage bias were-0.41％ (P ＞0.05) and-4.20％ (P ＜ 0.05),respectively.The expected percentage bias at three medical decision levels were-0.46％,-0.83％ and-0.96％ for urea and -15.90％,-5.87％ and-2.95％ for creatinine.Conclusions The results of urea analyzed by the routine chemistry system were consistent with the ID-MS method,which suggested that the results of the routine system procedure could be traced to ID-GC/MS method.For creatinine,the bias between the results of routine procedures and the assigned values met the minimum acceptance criteria' derived from biologic deviations,which would be better if its specificity improved.

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.