A1c and fasting glucose are often ordered together because they tell different parts of the blood sugar story.
What A1c shows
Hemoglobin A1c estimates average blood sugar over roughly the prior few months. It is commonly used for diabetes screening and monitoring.
What fasting glucose shows
Fasting glucose measures blood sugar at one point in time after a fasting period. It can move based on recent food, stress, illness, sleep, and other factors.
Why results can disagree
Because one is a trend marker and one is a point-in-time marker, A1c and fasting glucose can sometimes tell different stories. Certain blood conditions can also affect A1c interpretation.
Practical bottom line
A1c is useful for trend context. Fasting glucose is useful for a direct snapshot. Together, they are often more useful than either one alone.
Frequently asked questions
This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LabTestSuperstore does not diagnose, treat, or prescribe.