title: Elevated HbA1 due to foetal haemoglobinaemia in children. A common artifact of certain ion-exchange chromatography methods.
abstract: Foetal haemoglobin (HbF) is known to elute with glycosylated haemoglobins (HbA1) in mini-column ion-exchange chromatography, thus producing falsely elevated values for HbA1 in subjects with foetal haemoglobinaemia. We studied the occurrence of this methodological artifact in 266 patients with suspected or known insulin-dependent diabetes mellitus (IDDM) and in 205 healthy children of various age groups. HbA1 was measured using ion-exchange chromatography with prefabricated mini-columns and HbA1c and HbF by high-performance liquid chromatography (HPLC). In healthy children of over 5 years of age, the HbA1 values were usually within the reference limits for adults. However, 69% of the children younger than 1 year of age and 7% of those 1-5 years of age had HbA1 levels above 10%. Their HbA1c values were normal but the HbF values were high. Six of the 223 patients with IDDM (2.7%) and three of the 43 patients with stress glucosuria (7%) had much higher HbA1 than HbA1c values. The discrepancy was again related to the presence of raised concentrations of HbF. We conclude that foetal haemoglobinaemia is more prevalent than was previously known, especially among children younger than 5 years of age. Presence of HbF will bias the use of HbA1 as a diagnostic aid or as an index of metabolic control in children with IDDM. Methods specific for HbA1c, such as HPLC, should be used in paediatric patients.
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange / Q000379:methods* / Q000706:statistics & numerical data; D003922:Diabetes Mellitus, Type 1 / Q000097:blood; D005189:False Positive Reactions; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis*; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007223:Infant; D008297:Male; D012680:Sensitivity and Specificity
chemical_list: D005319:Fetal Hemoglobin; D006442:Glycated Hemoglobin