title: Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry-recommended reference measurement procedure and reference materials for glycated albumin determination.
abstract: 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. The stable isotopes of lysine and fructosyl-lysine, which serve as an internal standard, were added to albumin isolated from serum, followed by hydrogenation. After hydrolysis of albumin with hot hydrochloric acid, the liberated lysine and fructosyl-lysine were measured by liquid chromatography/tandem mass spectrometry, and their concentrations were determined from each isotope ratio. The reference materials (JCCRM611) for determining of glycated albumin were prepared from pooled patient blood samples.
  
  
  RESULTS
  The isotope dilution-tandem mass spectrometry calibration curve of fructosyl-lysine and lysine showed good linearity (r = 0.999). The inter-assay and intra-assay coefficient of variation values of glycated albumin measurement were 1.2 and 1.4%, respectively. The glycated albumin values of serum in patients with diabetes assessed through the use of this method showed a good relationship with routine measurement procedures (r = 0.997). The relationship of glycated albumin values of the reference material (JCCRM611) between these two methods was the same as the relationship with the patient serum samples.
  
  
  CONCLUSIONS
  The Committee on Diabetes Mellitus Indices of the Japan Society of Clinical Chemistry recommends the isotope dilution liquid chromatography/tandem mass spectrometry method as a reference measurement procedure, and JCCRM611 as a certified reference material for glycated albumin measurement. In addition, we recommend the traceability system for glycated albumin measurement.
authors.affiliation: Division of Internal Medicine, Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan.
authors.forename: Izumi
authors.initials: I
authors.lastname: Takei
authors.affiliation: Institute of Biopathological Medicine, Kanagawa Japan.
authors.forename: Tadao
authors.initials: T
authors.lastname: Hoshino
authors.affiliation: Division of Internal Medicine, Hananoie Hospital, Tochigi, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Tominaga
authors.affiliation: Department of Laboratory Medicine, New Tokyo Hospital, Chiba Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Ishibashi
authors.affiliation: Bio-Medical Standards Section, Organic Analytical Chemistry Division, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Kuwa
authors.affiliation: Reference Material Institute for Clinical Chemistry Standard (ReCCS), Kanagawa, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Umemoto
authors.affiliation: Japan Reference Measurement Institute, Kanagawa, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Tani
authors.affiliation: Institute of Biopathological Medicine, Kanagawa Japan.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Okahashi
authors.affiliation: Science and Technology Group, Diagnostics Department, Asahi Kasei Pharma, Tokyo, Japan Keiko-yasukawa@umin.ac.jp.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yasukawa
authors.affiliation: Science and Technology Group, Diagnostics Department, Asahi Kasei Pharma, Tokyo, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Kohzuma
authors.affiliation: Clinical Laboratory, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Asako
authors.initials: A
authors.lastname: Sato
mesh_terms: D001774:Blood Chemical Analysis / Q000592:standards*; D002853:Chromatography, Liquid; D017127:Glycation End Products, Advanced; D006801:Humans; D007564:Japan; D012015:Reference Standards; D012709:Serum Albumin / Q000032:analysis*; D012955:Societies, Medical; D053719:Tandem Mass Spectrometry; D000093423:Glycated Serum Albumin
chemical_list: D017127:Glycation End Products, Advanced; D012709:Serum Albumin; D000093423:Glycated Serum Albumin
keywords: Glycated albumin; isotope dilution mass spectrometry; reference material; secondary reference measurement procedure; standardization