[Glycosylation of hemoglobin and the minor hemoglobins : techniques and diagnostic study (author's transl)].

Hemoglobin Alc is the result of non-enzymatic binding of a glucose molecule at the NH2 terminal of the beta chain. Assay of glycosylated hemoglobin is of great utility for the control efficacity of antidiabetic treatments, since such levels provide the clinician with an excellent index of glucose metabolism over the weeks preceding the assay. Methods proposed for this assay include isoelectric focalization, colorimetric assays during thio-barbituric acid and especially, cation exchange chromatography. When automated, this last technique allows selective assay of Hb Alc and appears to provide the most accurate results. Certain causes of error must nevertheless be considered, in particular more rapid turnover of the erythrocytic population and the presence of Hb F which, in all chromatographic techniques, is eluted along with Hb Alc.