[Hemoglobin A1c: a new factor in the supervision of diabetes (author's transl)].

Hemoglobin A1c is one of the minor components of normal human hemoglobin. It differs from Hb A by the presence of one molecule of glucose fixed to the N-terminal extremity of every beta chain. It is synthesized from Hb A by a very slow and only slightly reversible mechanism which continuously occurs during the 120 days of the red cell life. Hb A1c represents nearly 5% of total hemoglobin of the normal subject. In patients suffering of diabetes mellitus, its level seems to reflect closely the degree of equilibrium of the disease for 4 to 5 weeks which preceeded the evaluation.