Abnormal concentration of stable HbA1 in non-diabetic patients.

To study its specificity for hyperglycemia, stable HbA1 was determined with ion-exchange chromatography in 240 patients consecutively hospitalized in the department of internal medicine and in a non-diabetic reference population. Reference values were found to increase significantly with age in the age groups less than 30, 30-60, and greater than 60 years. 41 patients had stable HbA1 more than 2 SD above the mean of the reference group and random blood glucose less than 7 mmol/l, and 21 of these were classified as non-diabetics according to data in medical records. Four non-diabetic patients had stable HbA1 higher than + 4 SD. One of them had haemoglobinopathia, one severe anaemia under cortisone treatment, one cortisone treated myelomatosis with renal insufficiency and severe anaemia, and one patient had lymphoma and renal insufficiency. Nine patients had stable HbA1 between + 3 and 4 SD and diagnoses of coronary heart disease (4), rheumatoid arthritis (2), asthma (1), chronic renal failure (1) and malignant melanoma (1). Five of them were treated with cortisone or diuretics. Four patients had stable HbA1 slightly below the reference range. In summary marked elevation of stable HbA1 due to factors other than diabetes occurred in a few patients with haematological disorders.