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We separately evaluated split specimens of serum for lipoprotein cholesterol in 38 five- to 14-year-old children, by the heparin/Ca2+ precipitation method and the ultracentrifugation/dextran sulfate precipitation method. Statistical analysis of the results indicated an excellent agreement (especially in beta- and alpha-lipoprotein cholesterol values) between results by the two methods. The percentage of alpha-lipoprotein cholesterol (mean +/- SD: 38.6 +/- 5.0) in children further confirmed the earlier observations that cholesterol derived from alpha-lipoprotein in children constitutes a relatively greater part of the serum total cholesterol than is true of adults.

We evaluated glycosylation of hemoglobin (HbA + HbA1) in 25 control subjects and in 133 diabetic patients who were in various stages of blood glucose control, by measuring ketoamine-linked hexoses in hemoglobin. These hexoses were converted by digestion with 10 mol/L acetic acid for 16 h at 100 +/- 5 degrees C to 5-hydroxymethylfurfuraldehyde, which was quantitated by reaction with 2-thiobarbituric acid. Glycosylation of hemoglobin was expressed as micromoles of hydroxymethylfurfuraldehyde per gram of globin protein (the "HMF index"). A mean HMF index of 1.67 (SD = 0.23) was obtained for controls; that for diabetic patients was 2.93 (SD 0.95). The index correlated well (r = 0.83, p < 0.001) with average blood glucose concentration as measured during the preceding 16 weeks, over a wide range of glucose values (1 to 6 g/L). It correlated even better (r = 0.92, p < 0.001) when corrected for variations in hemoglobin concentration. Thus measurement of ketoamine-linked hexoses of hemoglobin or HMF index provides an independent and useful alternative to the currently used methods that measure only HbA1 or HbA1c.