[Glycosylated hemoglobin in nonselected under-18-year-old young diabetics. Comparison of 2 HPLC methods]

The aim of this study is to determine, in an unselected population of diabetic children and adolescents < 18 years of age, which HbA1c levels can be achieved, and to compare 2 different HPLC (High Performance Liquid Chromatography) methods. One hundred and fourty-four unselected subjects (73 boys and 71 girls), with a diabetes duration ranging from 5 months to 15 years were included. HbA1c was measured simultaneously in our hospital and at the Steno Institute in Danemark. The mean (SD) HbA1c levels in the 144 children and adolescents were 6.6 +/- 1.2% using our method (normal values: 3.9-5.5%), and 7.7 +/- 1.1% at the Steno Institute (normal values : 4.4-6.3%), with a mean difference of 1.1 +/- 0.4%. Therefore, one must be cautious when comparing HbA1c levels, even by HPLC, between laboratories. Moreover, the lack of HbA1c standardization makes difficult to define HbA1c thresholds in order to avoid diabetic complications. In more than 60% of the patients, it is possible to obtain an HbA1c level under the normal mean value plus 5 SD. In the other paediatric studies, HbA1c levels are higher, whatever the type of treatment.