Good patient care requires accurate and comparable laboratory test results. To achieve standardization, a reference system consisting of a hierarchal framework of validated and reliable analytical methods linked by reference materials must be in place. Supported by national and municipal research programs, construction of reference systems has been pursued and progress been made. Candidate reference methods have been set up or developed for some important tests, and the methods have been used in the calibration or evaluation of routine methods, study of commutability of control materials and characterization of reference materials. Phenomenal roles of reference systems are expected in diagnostic reagent manufacturing, internal quality assurance and external quality assessments.

Roles of reference method in clinical biochemistry were introduced.Reference method is an important component of the reference system.Reference methods are primarily used for the establishment and assurance of the traceability of measurement results through calibrating and evaluating routine methods and assigning values to reference materials.Calibration biases and non-specificities of routine methods and the commutability of reference materials are the major issues in the standardization of clinical biochemistry.Standardization also requires availability of commutable reference materials.Reference methods are irreplaceable tools to identify the issues and to characterize reference materials.

Over the past years efforts have been made by the government to improve the management of clinical laboratories.The government activities such as networking of quality assurance, development and implementation of clinical laboratory standards, and establishment of external quality control mechanisms have facilitated the improvement of clinical laboratory quality.Further definition and integration of clinical laboratory services, introduction of clinical laboratory pathologists and consultation and establishment of a permission mechanism are needed for improving the effectiveness of clinical laboratory services.Government regulations will continue to play an essential role in the clinical improvement process.

specifications are essential for total quality management in laboratory medicine. A consensus among worldwide professionals has been achieved and a hierarchy of strategies for setting analytical quality specifications has been proposed based on their relevance to medical decision-making. Quality specifications derived from biological variations have been widely accepted because of their objectivity and practicability and have more and more been used in the quality management in laboratory medicine.

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 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.

A reference system for the completed blood count (CBC) have been established in National Center for Clinical Laboratory (NCCL) according to the standards published by International Council for Standardization in Hematology (ICSH) and International Organization for Standardization (ISO) in order to calibrate hematology analyzer.The contents of our study mainly include:(1)Establishment of calibration laboratory for CBC, which is the first calibration laboratory accepted by China National Accreditation Board for Laboratories in all medical laboratories.(2)We firstly set up the reference method for CBC in China. In addition, the data between NCCL and a foreign reference laboratory have been compared. (3)We have calibrated some instruments from routine laboratories by the fresh blood or calibrator valuated by the reference system, which acts as a new way to calibrate hematology analyzer.(4) A secondary standard assay system has been established and the data between it and the foreign reference laboratory have been compared chronically. The experience has been introduced to local laboratories in 26 provinces.(5) We have drafted out several documents about technical standard for laboratory medicine. The main institution of applications includes: local center for clinical laboratory, clinical laboratories for routine examination, institutions for identification to instruments and reagents, centers for disease control and prevention, and so on.

Objective To develop a candidate reference method for the determination of sodium in serum by inductively coupled plasma mass spectrometry method (ICP-MS). Methods Aluminum, as internal standard of sodium, was added into serum samples and sodium standard solutions by gravimetric analysis. The samples were digested by HNO3 and diluted, and its 23Na/27Al isotope ratios were obtained by ICP-MS. The sodium concentrations were calculated with the standard curve method in serum. Results The analytical recoveries of sodium were 100.67% and 100.15% respectively, and the precisions were 0.08% and 0.04% respectively for 2 different serum samples. The results of measuring sodium in serum of Standard Reference Material (SRM) gave the coefficients of variation (CVs) of 0.18% and 0.22% for 2 levels of standard reference material(SRM) 909b and 0.41%, 0.41% and 0.66% for 3 levels of SRM 956b. The relative deviations between the results and median of the certified value were 0.17% and 0.14% for 909b and -0.09%, -1.05%, -0.48% for 956b respectively. Conclusions The ICP-MS and aluminum internal standard method is proved to be not only precise and accurate, but also quick and convenient for measuring sodium in serum. It is promising to be a candidate reference method for determination of sodium in serum.

ObjectiveTo establish the reference intervals for ALT,AST,GGT and LDH among the Han nationality in Beijing.MethodsThe document C28-P3 issued by CLSI was a guideline about how to define,establish,and verify reference intervals in the clinical laboratory.IFCC had established multicenter enzymes reference intervals based on the guideline.Exclusion criteria were designed for screening candidate reference individual according to the document C28-P3 and the multicenter study's experience.Blood specimens were collected from 315 healthy individuals aged 20 to 60 years old,including 132 males and 183 females.Reference materials were used to ensure the accuracy of the test results of the four liver enzymes.The methods which used to test the four liver enzymes could be traced to the IFCC enzymes reference measure procedure,the reagent of ALT and AST included pyridoxal phosphate.Results There was statistically difference between males and females of the referenceranges forALT, ASTand GGT.Therefore,gender-specific reference intervals were established as ALT:8.2 -50.8 U/L (F),12.7 -71.8 U/L (M) ; AST:15.0 -36.7 U/L ( F),16.6 -51.1 U/L (M) ;GGT:9.0 -37.3 U/L (F),12.0 -50.9 U/L (M).For LDH,the reference interval was 127 -224 U/L,as no significant gender difference was found.ConclusionsThe reference intervals for the four liver enzymes based on the population of the Han nationality in Beijing are established.The upper reference limit for ALT in Beijing Han population is higher than that from other similar studies.