In laboratory medicine, accurate and comparable measurement results are required for correct medical interpretations.Metrological traceability is an important approach to achieve standardization of test results obtained with different analytic systems.Traceability is established by a series of comparative measurements using a hierarchy measurement procedures and calibrators.Specificity of the lower order methods and commutability of the calibrators are the prerequisites in establishing traceability.The higher order procedures and calibrators in the hierarchy are called reference systems and it is important that the reference systems are metrologically qualified.The Joint Committee for Traceability in Laboratory Medicine (JCTLM) has been formed to identify the reference systems worldwide.In conclusion, the concept of metrological traceability has been introduced to the filed of laboratory medicine.Development and implementation of reference systems in laboratory medicine are expected.

It is essential for measurements clinical biochemistry in to be adequately accurate to enable effective health and disease management.Quality assurance requires mechanisms for the surveillance of the analytical quality, identification of insufficiencies, and improvement of measurement performance. More effective quality assurance can be expected through further studies and researches on the construction of reference systems and standardization programs.

Diabetes is a worldwide epidemic disease in the twenty-first century.The most danger of diabetes is its complications which are the major cause of morbidity and mortality in diabetic patients.The development and progression of diabetes complications are directly associated with blood glucose levels,Hemoglobin A1c is not only the gold standard for the long-term blood glucose control of diabetic patients,but also the World Health Organization (WHO) recommended diagnosis of diabetes.Thus,a question has been raised:how to improve the comparability of hemoglobin A1c results meet clinical needs? At least four points should be taken in determining hemoglobin A1c:(1)Understand the interference factors; (2)Choose scientific and practical methodologies; (3)Standardized operation; (4)Regularly monitor the quality of testing results.

Fatty acid compositions of cholesteryl esters in 113 male adults of 4 nationalities in 5 districts in China were analyzed. Fatty acid patterns of cholesteryl esters in different population groups were similar, though some variations were observed which seemed to be caused by the difference in diet. The correlations of serum cholesteryl ester fatty acids with the quality and quantity of dietary fat and with the serum lipid levels were discussed.

Application of virtual experiment in the pathophysiology experimental teaching brings more vividness and interest,increases students'activities to complete experiments just like being in a real laboratory.it also relieves the contradiction between teaching requirements and experimental conditions effectiveIy,and take a new learning style to students and promote the changes of teachers'teaching model and teaching idea.

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.

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.

The shoulder joint is the largest joint of range of motion in the human body,but the stability is relatively low.Ath-letes and soldiers who engage in the high strength training are prone to shoulder joint instability, while Bankart lesion is the common factor which leads to shoulder joint instability.With the invention of the new medical devices and updating therapeutic method, the treatment of Bankart lesions is improved continuously.In this paper, we will review the key points of diagnosis and therapeutic method.

The incidence of thyroid dysfunction has increased year by year; the degree of public concern about thyroid disease also has been growing; the accuracy and comparability of results given by thyroid hormone assays from clinical laboratories face new challenges .This paper reviewed the clinical significance and measurements of thyroid hormones , also summarized the outcome of IFCC Working Group on Standardization of Thyroid Function Tests .It is expected to bring manufacturers′and clinical laboratories′attention to the importance of standardization/harmonization; and they could collaborate with each other .