Analysis and Quantitation of Glycated Hemoglobin by Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry

Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the beta-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R-2 > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of a parts per thousand currency sign 2.5%. Additional and independent measurements of glycation of the alpha-subunit of hemoglobin are used to validate beta-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.