Assessment of glycerol-related analytical bias in triglyceride estimation for patients with type 2 diabetes

INTRODUCTION: Standard triglyceride assays may overestimate true triglyceride concentrations due to endogenous glycerol interference, particularly in type 2 diabetes, where enhanced lipolysis elevates circulating free glycerol. We compared glycerol-blanked and non-blanked triglyceride assays in patients with type 2 diabetes to quantify analytical bias and assess impact on cardiovascular risk indices. METHODS: This cross-sectional study enrolled 200 patients with type 2 diabetes and 200 healthy control individuals. Serum triglyceride levels were measured using glycerol-blanked (Sekisui) and nonblanked (Beckman Coulter) enzymatic assays. Bias assessment, correlation analysis, and impact on atherogenic index of plasma were evaluated. RESULTS: Median nonblanked triglyceride values were substantially higher than glycerol-blanked triglyceride values in control individuals (129.5 vs 120.95 mg/dL, P = .02) and patients with type 2 diabetes (158.5 vs 136.85 mg/dL, P = .0019). Overestimation was greater in patients (median difference, 16.1 mg/dL) than in control individuals (9.95 mg/dL, P = .0001). Bland-Altman analysis showed higher mean (SD) bias in patients with type 2 diabetes (-21.25 [41.51] mg/dL) than in control individuals (-13.26 [31.26] mg/dL). The triglyceride- glycerol-blanked triglyceride difference correlated with glycated hemoglobin values in individuals with type 2 diabetes (ρ = 0.141, P = .0473). DISCUSSION: Glycerol-blanked triglyceride assays provide more accurate lipid assessment in type 2 diabetes, improving cardiovascular risk stratification and therapeutic decision-making.