HbA1c result, does it depend upon the testing methods?

© Japi • January 2014 • Vol. 62  9 I n o r m a l h u m a n e r y t h r o c y t e s , HbA comprises > 90% of the total haemoglobin. Besides HbA, human erythrocytes contain other haemoglobin components that are of considerable interest. Some of these, such as HbA2 and foetal haemoglobin (HbF), like s i c k l e c e l l h a e m o g l o b i n , a r e t h e products of al ternate globin chain genes and others such as HbA1c are post translational modifications of HbA. The haemoglobin A (Hb A) is converted to HbA1c by interacting with glucose with the amino group of the N-terminal valine of goblin chain when glucose enters inside the RBC. This process is a purely intracellular process and is influenced by the concentration of glucose within RBC. Glycation may occur at other sites, producing HbA1 other than HbA1c. Ion exchange chromatography separates specifically HbA1c, whereas weak acid hydrolysis tests detect all the glycation sites of HbA. Therefore, a clinician must search for the method of detection before interpreting the results of Glycated Haemoglobin( GHb) if to be done in a flawless way.1