A pilot study: effect of erythrocyte lifespan determined by a modified carbon monoxide breath test on glycosylated hemoglobin interpretation.

Glycosylated hemoglobin (HbA1c) is an important criterion for the diagnosis of diabetes and an indicator of the blood glucose level. The red blood cell (RBC) lifespan heterogeneity is sufficient to influence the HbA1c interpretation. In this study, we recruited 120 patients with diabetes mellitus and 85 nondiabetic controls. The HbA1c and the RBC lifespan were detected by high-performance liquid chromatography and the advanced carbon monoxide breath detection method, respectively. Potential correlations of gender and age with HbA1c were analyzed and a receiver operator characteristic curve was generated to get the HbA1c cut-off for every RBC lifespan group. It was confirmed that HbA1c has no correlation with gender or age. The correlation formula between the HbA1c diagnostic criteria and RBC lifespan was derived to correct the HbA1c diagnostic criteria using the least-square method. The RBC-lifespan-corrected HbA1c diagnostic criteria provided 100% sensitivity and specificity for the diagnosis of diabetes in the experimental set and was not refuted in the validated set. The diagnostic value of HbA1c is positively correlated with the RBC lifespan, and four patients with hyperglycemia, whose HbA1c values were lower than the general diagnosis criterion of 6.5%, were still considered to be diabetic according to this formula; that is, the application of this formula may help us to eliminate the 2.2% misdiagnosis rate of the current diagnostic criteria. To provide more accurate detection results, the effect of the RBC lifespan needs to be taken into account when HbA1c is used as a clinical indicator.