HbA1c to Estimated Average Glucose (eAG)
Converts HbA1c percentage to estimated average glucose (eAG) in mg/dL or mmol/L using the ADAG study formula endorsed by ADA, EASD, and IDF.
Warnings:
- Formula derived from the ADAG study with ~500 subjects across 10 international centers
- eAG correlates strongly with HbA1c but does NOT equal fasting plasma glucose
- HbA1c can be unreliable in conditions affecting hemoglobin (anemia, hemoglobinopathies, pregnancy, uremia)
- IFCC reference method reports HbA1c in mmol/mol; conversion: mmol/mol = (DCCT % - 2.15) x 10.929, % = (mmol/mol x 0.0915) + 2.15
- ADA recommends reporting eAG alongside HbA1c to help patients understand glycemic control
Note: Reference eAG ranges: HbA1c 5% = eAG 97 mg/dL; 6% = 126 mg/dL; 7% = 154 mg/dL; 8% = 183 mg/dL; 9% = 212 mg/dL; 10% = 240 mg/dL.
Glycated hemoglobin value as percentage (DCCT/NGSP units)
References
- The association between estimated average glucose levels and fasting plasma glucose levels - Cureus / PMC (2010)
- Translating the A1C assay into estimated average glucose values - Diabetes Care (ADAG Study) (2008)