Effect of acetaldehyde and acetylsalicylic acid on HbA1c chromatography in the FPLC method with Mono S cation exchanger.

The effects of alcohol and aspirin on HbA1c chromatography in the Mono S method were studied in vitro and in vivo. A modified chromatography with enhanced resolution was used, making possible detailed examination of minor interfering peaks included in the routine HbA1c value. Incubation with acetylsalicylic acid increased a hemoglobin fraction separate from HbA1c. In vivo this fraction was elevated by 0.1% of the total hemoglobin during therapeutic aspirin ingestion for one month. In vitro acetaldehyde generated two labile hemoglobin fractions and slightly increased a minor stable fraction which was also elevated in vivo in both alcoholics and heavy drinkers. In relation to the HbA1c concentration, this stable fraction was equal in both alcoholic groups. We conclude that the in vivo effects of both aspirin and alcohol are negligible in routine HbA1c determination. Factors other than acetaldehyde might account for the unexpected HbA1c values in alcoholics.

Does uremia interfere with HbA1c results in the FPLC method with Mono S cation exchanger?

To study the effect of uremia on hemoglobin A1c determination by the Mono S FPLC method, samples from uremic patients, with and without diabetes, and controls, were analysed with a modified chromatography with enhanced resolution. Besides specific HbA1c, four minor peaks could be seen, included in routine HbA1c values. Two of these differed in concentration in the patient groups studied: a shoulder-like peak close to the specific HbA1c (S fraction) and a slightly less cationic minor peak (M fraction). Both S and M peaks were higher in uremic than in nonuremic subjects, but the M peak was associated more with diabetes. In the nondiabetic group, the mean routine HbA1c value was 0.8% units higher in uremic than nonuremic individuals. The specific HbA1c was nondependent on uremia. Thus, in uremic patients, there seems to be falsely elevated HbA1c values, mainly because of small interfering hemoglobin fractions, not specific HbA1c.

Specificity of hemoglobin A1c measurement by cation exchange liquid chromatography. Evaluation of a Mono S column method.

A method was developed for evaluating the specificity of the ion exchange chromatographic HbA1c method by Pharmacia which uses a Mono S column. To investigate hemoglobin fractions potentially interfering in HbA1c analysis, the chromatographic resolution was enhanced and a peak integration program was used which enables the quantitation of overlapping and even shoulder-like peaks. Hemoglobin was incubated with glucose in vitro and the chromatograms were analyzed before and after incubation. Five minor peaks were detected, close to hemoglobin A1c, which could not be conclusively identified as hemoglobins previously described. Four of these peaks, the stable ones, were included in the fraction of the chromatogram to be measured as HbA1c by the routine method. In practice, these peaks comprise 20%-35% of the routine HbA1c result in diabetic patients and 30%-45% in non-diabetic subjects. Three of these minor peaks were non-dependent on glucose. The chromatography and the peak integration method described can also be used to study hemoglobin adducts other than glycohemoglobin.

Fetal hemoglobin in diabetic patients.

OBJECTIVE: To determine the occurrence of elevated fetal hemoglobin (HbF) among the diabetic population and determine the clinical situation of importance. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted. HbA1c and HbF were measured with high-performance liquid chromatography in 1,104 consecutive diabetic patients attending our clinic for HbA1c determination. The expression of clinical correlations between the high and low HbF group was performed for adults (> or = 15 years). A nondiabetic control group (n = 258) with the same age and sex distribution was included. RESULTS: HbF was elevated (> 1.0% of total hemoglobin) in 7.5% of the total diabetic group. In the adult diabetic group, HbF was elevated in 6.5% of the patients, and in the control group, HbF was elevated in 1.9% (P < 0.01). In the insulin-treated adult group, HbF was elevated in 10.2% of the patients, and in the non-insulin-treated group, HbF was elevated in 3.8%. The mean HbA1c was 8.90 +/- 2.00% among the patients and 5.52 +/- 0.53% in the control subjects (P < 0.001). Patients with elevated HbF were younger (P < 0.02) and more often on insulin therapy (P < 0.001) or type I diabetic patients (P < 0.001). Sex, glycemic control, or duration of diabetes were not significantly different in the patients with high or low HbF. Correlation was not detected between the amount of HbF and HbA1c or age in the group of patients with elevated HbF. Hemoglobinopathies, anemias, or malignancies were not diagnosed from the patients with high HbF. CONCLUSIONS: Level of HbF is increased (> 1.0%) among 7.5% of unselected diabetic patients. In adult (> or = 15 years) diabetic patients, it is increased among 6.5%, which is 3.4 times more often than in the control population. Acute hematological conditions or malignancies do not explain the difference. Elevated HbF seems to be associated with type I diabetes and insulin treatment.