Evaluation of MALDI-TOF MS for the measurement of glycated hemoglobin

Background: Glycated hemoglobin (Hemoglobin A(1c), HbA(1c)) plays a key role in monitoring long-term blood glucose levels in diabetics mellitus. Therefore, it is of great importance to ensure test quality of HbA1c methods. Objectives: We aimed to evaluate analytical performances of a matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) system for the measurement of HbA(1c). Methods: We assessed the analytical performances of the method including imprecision, accuracy, and linearity. In addition, comparison with Variant II Turbo 2.0 and Capillarys3 TERA, correlation between glycation rate of a and beta globin as well as the influence of most frequent analytical interferences in HbA(1c) assays were also investigated. Results: As measurement of imprecision, within-run CVs and total CVs were lower than 1.6% and 2.4%, respectively. Discrepancy of test results (<0.2%) of IFCC value-assigned external quality control samples indicated a good accuracy of the method. The linearity was excellent with a correlation coefficient of 0.999. The QuanTOF results were well correlated with those obtained by Variant II Turbo 2.0 and Capillarys3 TERA. Good correlation between glycation rates of alpha and beta globin were found. QuanTOF was not prone to common interferences including bilirubin, triglyceride, labile A(1c), and carbamylated hemoglobin. However, unacceptable positive bias was observed when the amount of HbF were greater than approximately 8.0% or in the presence of HbS. Conclusions: QuanTOF perform well for the determination of HbA(1c) and meet quality criteria requested for clinical use.