Incidence of abnormalities in laboratory tests found in surveillance of adults over 40 years of age.

National health check-up systems have been used for 5 years in Japan for adults who are over 40 years of age. As part of a national project, Osaka prefecture is also conducting a program for health check-up testing and cancer screening for this age group. This surveillance revealed that incidence of obesity, hypertension, cholesterolemia, albuminuria, or abnormal ECG was high. Analysis of surveillance results should contribute to understanding the present status and recent trends in diseases in the aged. With continuation of this surveillance for a number of years, trends in life-style related diseases in Japan should be detectable.

Country reports from Japan: external quality assessment scheme in Japan.

Several external quality assessment schemes (EQAS) have been conducted in Japan. Results obtained from nation-scale EQAS reveal the current quality of laboratory testing in each laboratory. The largest nation-scale EQAS in Japan is that conducted by the Japan Medical Association. The numbers of participants and of items evaluated have increased in EQAS by JMA over its history of 32 years. Improvement in inter-laboratory differences has been observed for most items in EQAS in recent decades. In 1998, about 2,500 laboratories from throughout the country participated in this surveillance, and 47 items were evaluated. The coefficient of variations for the group of all participants was less than 5% for about one third of all test items. On the other hand, very high variations over 20% were observed for 6 items. Also, inter-method differences exist for many items, which may be or may not be related to matrix effects. Retrospective evaluation of all EQAS data suggests that there is still room for improvement in inter-laboratory differences.

Quality control in a manual and an automated leukocyte differential count.

Quality control (QC) has been introduced in laboratories, and QC surveys in leukocyte differential count to enhance quality have been performed by College of American Pathologists, Japanese Association of Medical Technologists, Osaka Medical Association and manufacturers. The results of QC survey in a manual leukocyte differential count indicated problems on the differentiation of segmented neutrophils and band neutrophils and the detection of pathological blood cells on blood smear. While the results of QC survey in an automated leukocyte differential count performed by same manufacturer with an automated blood cell counter were satisfactory, however, there was a difference in leukocyte differential cell counts among laboratories with other manufacturer's instruments because the synthetic blood material used in QC is an exclusive item for an instrument. It is necessary to further reeducate the medical technologists in order to improve morphological performance, and to standardize the synthetic blood material for compatibility with various automated blood cell counters.

External quality control results for hormones, tumor markers and CRP testing.

Most hormones, tumor markers, C-reactive protein, and rheumatoid factor (RF) are measured immunologically. Immunological methods based on the antigen-antibody reaction have certain specific problems, including their principle of determination, character of antibodies used, reaction conditions, and others. Free thyroxine (FT4) and thyroid stimulating hormone (TSH), as well as alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), prostate antigen, carcinoantigen 19-9 (CA 19-9), and CA 125 are very commonly measured in the routine medical laboratory. Authentic materials can be obtained for hormones and CRP, and efforts to improve quality control and standardization have been made for years. Results of surveillance for FT4, TSH, and AFP were not poor, but inter-laboratory differences for CEA, CA 19-9, and RF were not insignificant.

Quality control in urinalysis.

Quality control (QC) has been introduced in laboratories, and QC surveys in urinalysis have been performed by College of American Pathologist, by Japanese Association of Medical Technologists, by Osaka Medical Association and by manufacturers. QC survey in urinalysis for synthetic urine by the reagent strip and instrument made in same manufacturer, and by an automated urine cell analyser provided satisfactory results among laboratories. QC survey in urinalysis for synthetic urine by the reagent strips and instruments made by various manufacturers indicated differences in the determination values among manufacturers, and between manual and automated methods because the reagent strips and instruments have different characteristics, respectively. QC photo survey in urinalysis on the microscopic photos of urine sediment constituents indicated differences in the identification of cells among laboratories. From the results, it is necessary to standardize a reagent strip method, manual and automated methods, and synthetic urine.