Effect of hemoglobin, triglyceride, and urea in different concentrations on compatibility between methods used in HbA1c measurement

Objectives The variability between methods is seen in the existence of hemoglobin (Hb), triglyceride (TG), blood urea nitrogen (BUN) and glucose in the specimens, which can affect the measurement. Therefore, this study aimed to compare boronate affinity chromatography and turbidimetric inhibition immunoassay methods for HbA1c levels in samples containing different levels of Hb, TG, BUN and glucose. Methods In this study, a total of 412 consecutive samples were used for method comparison. The samples were divided into groups according to HbA1c, TG, BUN, Hb, and glucose levels. Clinically significant changes for HbA1c are defined as >= 0.5%. Results The mean relative difference as % was determined as 1.4% by the Bland-Altman plot of Trinity against Roche. The Passing-Bablok analysis indicated good agreement (r=0.985) between two methods. When compared the group with and without a clinically significant difference, we found differences only between glucose levels (p=0.003). Conclusions High glucose levels may cause a difference between the methods. Therefore, we suggest that a method's performance and properties should be considered prior to clinical usage