Mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) correlated negatively with Hb A1c. Fasting glucose, MCH, and age emerged as predictors of Hb A1c in a stepwise regression that discarded sex, hemoglobin, MCV, mean corpuscular hemoglobin concentration (MCHC), serum creatinine, and liver disease. Mean Hb A1c in MCH interdecile intervals fell from 6.8% (51 mmol/mol) in the lowest (≤27.5 pg) to 6.0% (43 mmol/mol) in the highest (>32.5 pg), with similar results for MCV. After adjustment for fasting glucose and other correlates of Hb A1c, a 1 pg increase in MCH reduced the odds of Hb A1c–defined dysglycemia, diabetes and poor glycemia control by 10%–14%.
For at least 25% of patients, low or high MCH or MCV levels are associated with increased risk of an erroneous Hb A1c–based identification of glycemia status. Although causality has not been demonstrated, these parameters should be taken into account in interpreting Hb A1c levels in clinical practice.
Impact of Mean Cell Hemoglobin on Hb A1c–Defined Glycemia Status
Source: Clinical Chemistry