Izumi Takei1, Tadao Hoshino2, Makoto Tominaga3, Midori Ishibashi4, Katsuhiko Kuwa5, Masao Umemoto6, Wataru Tani7, Mikiko Okahashi2, Keiko Yasukawa8, Takuji Kohzuma9, Asako Sato10. 1. Division of Internal Medicine, Tokyo Dental College, Ichikawa General Hospital, Chiba, Japan. 2. Institute of Biopathological Medicine, Kanagawa Japan. 3. Division of Internal Medicine, Hananoie Hospital, Tochigi, Japan. 4. Department of Laboratory Medicine, New Tokyo Hospital, Chiba Japan. 5. Bio-Medical Standards Section, Organic Analytical Chemistry Division, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan. 6. Reference Material Institute for Clinical Chemistry Standard (ReCCS), Kanagawa, Japan. 7. Japan Reference Measurement Institute, Kanagawa, Japan. 8. Science and Technology Group, Diagnostics Department, Asahi Kasei Pharma, Tokyo, Japan Keiko-yasukawa@umin.ac.jp. 9. Science and Technology Group, Diagnostics Department, Asahi Kasei Pharma, Tokyo, Japan. 10. Clinical Laboratory, Tokyo Women's Medical University, Tokyo, Japan.
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. CONCLUSION: 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.
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. CONCLUSION: 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: Michael Bergman; Muhammad Abdul-Ghani; Ralph A DeFronzo; Melania Manco; Giorgio Sesti; Teresa Vanessa Fiorentino; Antonio Ceriello; Mary Rhee; Lawrence S Phillips; Stephanie Chung; Celeste Cravalho; Ram Jagannathan; Louis Monnier; Claude Colette; David Owens; Cristina Bianchi; Stefano Del Prato; Mariana P Monteiro; João Sérgio Neves; Jose Luiz Medina; Maria Paula Macedo; Rogério Tavares Ribeiro; João Filipe Raposo; Brenda Dorcely; Nouran Ibrahim; Martin Buysschaert Journal: Diabetes Res Clin Pract Date: 2020-06-01 Impact factor: 5.602
Authors: Cyrus V Desouza; Richard G Holcomb; Julio Rosenstock; Juan P Frias; Stanley H Hsia; Eric J Klein; Rong Zhou; Takuji Kohzuma; Vivian A Fonseca Journal: J Clin Endocrinol Metab Date: 2020-03-01 Impact factor: 5.958