We report a case of a diabetic patient with hemoglobinopathy who had an abnormally high HbA1c value measured by cation-exchange high performance liquid chromatography (HPLC) but had moderate HbA1c level measured by a new immunoassay system. A 43-year-old man with non-insulin-dependent diabetes mellitus was referred to our hospital because of a disproportionately high HbA1C value (22.4%) relative to the plasma levels of glucose and fructosamine. Since a falsely elevated value of HbA1c due to the presence of abnormal hemoglobins was suspected, further analysis was performed and the patient was shown to have Hb J Cape Town, α92 (FG4) Arg-Gln. Therefore, to measure HbA1c in this patient, we applied a newly developed immunoassay system specific for the Amadori product of the three N-terminal amino acid residues of the β-chain of the HbA1c molecule. Using this immunoassay system, the patient was found to have an HbA1c level (6.3%), comparable to that of fructosamine (238 μmol/l). These findings indicate that the new immunoassay system is applicable to the measurement of HbAI c levels in diabetic subjects with certain types of hemoglobinopathy in whom the standard HPLC method cannot be used to assess glycemic control.
Glycemic control by continuous subcutaneous insulin infusion (CSII) therapy in patients with IDDM was worse after treatment with short-acting neutral human insulin with m-cresol and without a buffer (B) than during treatment with short-acting neutral human insulin with methyl p-hydroxybenzoate and buffer (A). We assessed 6 women and 2 men with IDDM, aged 38-61 years, 3 of whom had simple retinopathy or albuminuria. They were treated with CSII using A insulin for more than 2 years.The means (±SD) of mean blood glucose per day, mean amplitude of glycemic excursion, glycohemoglobin A1C and fructosamine were 108±43 mg/dl, 67±27 mg/dl, 6.6±1.9% and 323±58/2mol/l, respectively, indicating that good glycemic control had been achieved. There was no trouble in any of the patients. One month after treatment with CSII using B insulin, the parameters had significantly (p<0.05) increased to 183±48 mg/dl, 142±73 mg/dl, 6.9±1.1% and 348±721umol/l, respectively, and this persisted for 3 months.In all patients, insulin delivery via the catheter was frequently occluded, causing pump failure in 1 patient, bone fracture due to severe hypoglycemia in 1 patient and acute pneumonia in 1 patient. The results indicate that the type of insulin preparation used in CSII is important, since insulin may be aggregated byauxiliar substances in insulin preparation. Resolving this problem will be a major issue in the future.