Comparison of Hba1c Level Measured by HPLC and Capillary Electrophoresis Among Patient With High Urea

Abstract

Utilization of glycated haemoglobin (HbA1c) in diagnosis and monitoring of diabetes mellitus is accepted and validated worldwide. Standardisation between various methods available is no longer an issue. However, knowledge of HbA1c interference by various haemoglobin (Hb) fractions presence in the patient’s sample must be taken into account during HbA1c analysis and interpretation. Carbamylated Hb (cHb) is one of Hb fractions, formed when Hb condensed at the N-terminal valine by cyanate derived from spontaneous decomposition of urea which usually raised in patients with renal impairment. This study aimed to compare the level of HbA1c in patient with high urea measured using High Performance Liquid Chromatography (HPLC) and Capillary Electrophoresis (CE). After analysis using the laboratory’s routine method, or HPLC, the patient’s samples with concurrent urea level of >25 mmol/L were re-analyzed within 2 hours using the comparative method or CE. A cut off cHb of 2% on HPLC considered as no interference. The mean level of urea was 31.37±5.09 mmol/L (range 25.2-43.1mmol/L). Out of 68 samples, only 24 cHb were detected by HPLC but only less than 2% and none cHb detected on CE. Correlation between HPLC and CE showed no significant different in HbA1c measurement (r= p>0.05). Therefore, we propose that both HPLC and CE can be used to determine HbA1c level in patient with high urea.