Estimated Average Glucose helps evaluate average daily blood glucose levels over the past three months. The calculation is based on hemoglobin A1C levels but is reported in mg/dL or mmol/L, the same way fasting, or postprandial glucose is reported.
The Estimated Average Glucose (eAG) translates hemoglobin A1C results, expressed as a percentage, into the same units used to measure blood glucose, i.e., mg/dL or mmol/L. Both markers help evaluate blood glucose control over the past 2-3 months.
Estimated average glucose reflects variability in glucose levels and is different from a single marker such as fasting glucose, which simply takes a “snapshot” of glucose levels at one point in time. It is important to know whether glucose levels are highly variable, as “excursions” can be more metabolically disruptive. However, as glucose regulation worsens, the association between fasting glucose and eAG becomes stronger (Alzahrani 2020, Ram 2021, Bozkaya 2010).
You can read more about Estimated Average Glucose on the ODX Research Blog: https://www.optimaldx.com/research-blog/biomarkers-of-blood-glucose-regulation-estimated-average-glucose
References
Alzahrani, Nabeel et al. “Can Fasting Blood Sugar be Used as an Indicator of Long-Term Diabetic Control Instead of Estimated Average Glucose?.” Clinical laboratory vol. 66,12 (2020): 10.7754/Clin.Lab.2020.200324. doi:10.7754/Clin.Lab.2020.200324
Bozkaya, Giray et al. “The association between estimated average glucose levels and fasting plasma glucose levels.” Clinics (Sao Paulo, Brazil) vol. 65,11 (2010): 1077-80. doi:10.1590/s1807-59322010001100003
Ram, Nanik et al. “Relationship Between Estimated Average Glucose (eAG) and Fasting Plasma Glucose in a Cohort of Pakistani Diabetic Subjects.” Cureus vol. 13,10 e18435. 2 Oct. 2021, doi:10.7759/cureus.18435