Improvement in glycemic control through changes in insulin regimens: findings from a Japanese cohort of children and adolescents with type 1 diabetes.

Objective: Although insulin analogs have dramatically changed diabetes treatment, scarce evidence is available on those effects. We aimed to explore whether glycemic control had improved, the use of insulin analogs had been increased, and hypoglycemic events had decreased over time in Japanese pediatric patients with type 1 diabetes (T1D).

Methods: Glycated hemoglobin A1c (HbA1c) values, proportion of insulin regimens, incidence of severe hypoglycemic events, and pubertal increase in HbA1c were compared in three cohorts of childhood-onset Japanese T1D patients (567 subjects in the 1995 cohort, 754 subjects in the 2000 cohort, and 806 subjects in the 2008 cohort).

Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry-recommended reference measurement procedure and reference materials for glycated albumin determination.

Background: Glycated albumin is an intermediate glycaemic control marker for which there are several measurement procedures with entirely different reference intervals. We have developed a reference measurement procedure for the purpose of standardizing glycated albumin measurements.

Methods: The isotope dilution liquid chromatography/tandem mass spectrometry method was developed as a reference measurement procedure for glycated albumin.

Report on HbA1c Proficiency Testing in Asia in 2012.

In 2010, the Japan Diabetes Society decided to introduce the National Glycohemoglobin Standardization Program (NGSP) values into clinical practice. Accordingly, NGSP Certification of Japanese manufacturers of HbA1c-related diagnostic reagents and instruments was initiated in February, 2012, through an NGSP network laboratory, the Asian Secondary Reference Laboratory (ASRL) #1. Traceability to the NGSP reference system can be endorsed by manufacturer certification, as well as by the College of American Pathologists (CAP) survey.

The ratio of glycated albumin to hemoglobin A1c measured in IFCC units accurately represents the glycation gap.

The glycation gap (G-gap: difference between measured hemoglobin A1c [A1C] and the value predicted by its regression on the fructosamine level) is stable and associated with diabetic complications. Measuring A1C level in International Federation of Clinical Chemistry (IFCC) units (A1C-SI; mmol/mol) and National Glycohemoglobin Standardization Program units (A1C-NGSP; %) and using glycated albumin (GA) level instead of fructosamine level for calculating the G-gap, we investigated whether the G-gap is better represented by GA/A1C ratio if expressed in SI units (GA/A1C-SI ratio) rather than in NGSP units (GA/A1C-% ratio). We examined 749 Japanese children with type 1 diabetes using simultaneous GA and A1C measurements.

[The worldwide standardization of hemoglobin A1c measurement: the current statement from the Japan Diabetes Society and the issues to be solved].

The American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) have recently decided to use both units in the hemoglobin A1c (HbA1c) measurement based on the NGSP (previously called the National Glycohemoglobin Standardization Program) and the IFCC (International Federation of Clinical Chemistry) in articles and scientific meetings, whereas each country or region may use either NGSP units (conventional %) or IFCC units (SI; mmol/mol) in common practice. This is expressed as "a new twist on the path to harmony" in the measurement of HbA1c. Accordingly, the Japan Diabetes Society has used only NGSP units as of April 1, 2013, whereas the previous JDS units will be used for the high reproducibility of the JDS Standardization System but not in the clinical setting.

Estimation and analysis of preference heterogeneity in residential choice behaviour.

Effective and efficient planning and development of residential environments require clarifying the nature of residential preferences. In reality, residential preferences are heterogeneous, so the standard econometric models that assume only one type of preference are not optimal. In this study, conjoint choice experiment methods are employed with a mixed logit approach.

Statistical methods for monitoring the relationship between the IFCC reference measurement procedure for hemoglobin A1c and the designated comparison methods in the United States, Japan, and Sweden.

Background: The American Diabetes Association (ADA)/European Association for the Study of Diabetes (EASD)/International Diabetes Federation (IDF)/IFCC Consensus Statement on the worldwide standardization of HbA(1c) states that "...

The IFCC Reference Measurement System for HbA1c: a 6-year progress report.

Background: The IFCC Reference Measurement System for hemoglobin (Hb)A(1c) (IFCC-RM) has been developed within the framework of metrologic traceability and is embedded in a network of 14 reference laboratories. This paper describes the outcome of 12 intercomparison studies (periodic evaluations to control essential elements of the IFCC-RM).

Methods: Each study included: unknown samples (to test individual network laboratories); known samples (controls); recently manufactured calibrators (to check calculated assigned value); stored calibrators (to test stability) and a calibration-set (to calibrate the IFCC-RM).

Global standardization of glycated hemoglobin measurement: the position of the IFCC Working Group.

The measurement of glycated hemoglobin is central in the monitoring of glycemic control in patients with diabetes. There are at least 30 different laboratory assays commercially available to measure the proportion of HbA1c in blood. In 1995 the IFCC established a Working Group (IFCC WG-HbA1c) to achieve international standardization of HbA1c measurement.

Japanese standard reference material JDS Lot 2 for haemoglobin A1c. II: Present state of standardization of haemoglobin A1c in Japan using the new reference material in routine clinical assays.

Background: In 2001, the Committee on Standardization of Laboratory Testing Related to Diabetes Mellitus of the Japan Diabetes Society (JDS) prepared and certified a new reference material for haemoglobin A1c (HbA1c), Lot 2. The standardization programme for HbA1c measurement in Japan is currently based on Lot 2, although some laboratories still use the previous material (Lot 1). The values assigned to Lot 2 were based on the consensus values for Lot 1 and should give the same results.

Japanese standard reference material for JDS Lot 2 haemoglobin A1c. I: Comparison of Japan Diabetes Society-assigned values to those obtained by the Japanese and USA domestic standardization programmes and by the International Federation of Clinical Chemistry reference laboratories.

Background: The Committee on Standardization of Laboratory Testing Related to Diabetes Mellitus of the Japan Diabetes Society (JDS) previously recommended use of the primary calibrator (JDS Lot 1) prepared by the former Committee for Standardization of Glycohemoglobin for standardizing the measurement of haemoglobin A1c (HbA1c). Owing to the depletion of vials of Lot 1 in March 2001, the present committee certified a new reference material, Lot 2, now distributed by the Health Care Technology Foundation (HECTEF). The standardization programme for HbA1c measurement in Japan is currently based on Lot 2, which has values assigned from within Lot 1; the Lot 1 values were consensus values based on assays by laboratories in the Japanese national quality control programme.

IFCC reference system for measurement of hemoglobin A1c in human blood and the national standardization schemes in the United States, Japan, and Sweden: a method-comparison study.

Background: The national programs for the harmonization of hemoglobin (Hb)A(1c) measurements in the US [National Glycohemoglobin Standardization Program (NGSP)], Japan [Japanese Diabetes Society (JDS)/Japanese Society of Clinical Chemistry (JSCC)], and Sweden are based on different designated comparison methods (DCMs). The future basis for international standardization will be the reference system developed by the IFCC Working Group on HbA(1c) Standardization. The aim of the present study was to determine the relationships between the IFCC Reference Method (RM) and the DCMs.

Approved IFCC reference method for the measurement of HbA1c in human blood.

HbA1C is the stable glucose adduct to the N-terminal group of the beta-chain of HbA0. The measurement of HbA1c in human blood is most important for the long-term control of the glycaemic state in diabetic patients. Because there was no internationally agreed reference method the IFCC Working Group on HbA1c Standardization developed a reference method which is here described.