Absorption Spectroscopy for the Estimation of Glycated Hemoglobin (HbA1c) for the Diagnosis and Management of Diabetes Mellitus: A Pilot Study Madhukar Mallya, MSc, PhD, 1 Revathi Shenoy, MSc, PhD, 2 Gopalkrishna Kodyalamoole, MSc, PhD, 2 Monalisa Biswas, BSc, 2 Jisha Karumathil, BSc, 2 and Sudha Kamath, MSc, PhD 3 Abstract Objective: The purpose of this study was to explore the possibility of using absorption spectroscopy technique for the estimation of glycated hemoglobin HbA1c (%) . Background data: Glycated hemoglobin (HbA1c) is an important marker in the diagnosis and management of diabetes mellitus. Different assay techniques have been employed for the estimation of glycated hemoglobin, including ion exchange high performance liquid chro- matography (HPLC), electrophoresis, affinity chromatography, immunoturbidimetric assay and colorimetric assays, which measure different glycated products and report using different units. Spectroscopic measurements have been shown to be very sensitive and nondestructive, and require very little quantity of material for analysis. In the present study, we have employed absorption spectroscopy technique for the estimation of glycated hemoglobin in hemolysate samples of diabetic patients. Materials and methods: The blood samples of individuals with normal glycemic status and confirmed diabetic patients were collected from the Clinical Bio- chemistry Laboratory, Kasturba Hospital, Manipal. The absorption spectra of glycated hemoglobin (HbA1c) samples were recorded in the spectral range 200–850 nm using an optic fiber based Ocean Optics CHEMUSB4- UV-VIS single beam spectrophotometer. The parameter ‘‘area under the curve’’ of each baseline corrected absorption spectrum was used for the estimation of HbA1c (%). The glycated hemoglobin values obtained by this spectroscopic method were compared with the values reported by the standard ion exchange HPLC method. Results: A total of 30 absorption spectra were recorded from hemolysate samples with HbA1c (%) in the range 4–10.5%. A good correlation was observed between the glycated hemoglobin values obtained by the spectro- scopic method and those obtained by the standard HPLC method. Conclusions: It appears that the direct absorption spectroscopy of hemolysate samples, therefore, may be utilized as a supplementary technique for the estimation of HbA1c (%), even at the primary healthcare centers. Introduction T he term ‘‘diabetes mellitus’’ describes a metabolic disorder with heterogeneous etiologies, which is charac- terized by chronic hyperglycemia and disturbances of car- bohydrate, fat, and protein metabolism resulting from defects in insulin secretion, insulin action, or both. 1 The long-term complications of diabetes have major consequences for indi- vidual subjects, and growing healthcare delivery and cost implications for society. Diabetes mellitus is a condition characterized by hyperglycemia resulting from body’s in- ability to use blood glucose for energy. In type 1 diabetes, the pancreas no longer makes insulin and, therefore, blood glu- cose cannot enter the cells to be used for energy. In type 2 diabetes, either the pancreas does not make enough insulin or the body is unable to use insulin correctly because of defect at receptor level. 2 The direct and indirect effects of hyperglyce- mia on the human vascular system are the major source of morbidity and mortality in both type 1 and type 2 diabetes. These effects include macrovascular complications (coronary artery disease, peripheral arterial disease, and stroke) and microvascular complications (diabetic nephropathy, neurop- athy, and retinopathy). 3 Diabetes mellitus affects *7% of the world population. 4 Therapy for diabetes requires the 1 Department of Biochemistry, KMC International Center, Manipal University, Manipal, Karnataka, India. 2 Department of Biochemistry, KMC, Manipal University, Manipal, Karnataka, India. 3 Department of Biophysics, KMC International Center, Manipal University, Manipal, Karnataka, India. Photomedicine and Laser Surgery Volume 31, Number 5, 2013 ª Mary Ann Liebert, Inc. Pp. 219–224 DOI: 10.1089/pho.2012.3421 219