What A1c (glycated hemoglobin) level corresponds to an average blood sugar of 104 mg/dL (milligrams per deciliter)?

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A1C Value Corresponding to Average Blood Sugar of 104 mg/dL

An average blood sugar of 104 mg/dL corresponds to an A1C of approximately 5.2%. 1

Correlation Between A1C and Average Blood Glucose

  • The relationship between A1C and average blood glucose is based on the international A1C-Derived Average Glucose (ADAG) study, which showed a strong correlation (r = 0.92) between these measurements 2
  • According to the American Diabetes Association's Standards of Medical Care, an A1C of 5% corresponds to an estimated average glucose (eAG) of 97 mg/dL (range 76-120 mg/dL) 2, 1
  • An A1C of 6% corresponds to an eAG of 126 mg/dL (range 100-152 mg/dL) 2, 1
  • Since 104 mg/dL falls between 97 mg/dL (A1C 5%) and 126 mg/dL (A1C 6%), the corresponding A1C would be approximately 5.2% 1

Clinical Interpretation of This Value

  • An A1C of 5.2% is within the normal range (below 5.7%), indicating no diabetes or prediabetes 2, 1
  • For reference, prediabetes is defined as A1C between 5.7-6.4% 2, 1
  • Diabetes is diagnosed when A1C is ≥6.5% 2

Factors That May Affect A1C Interpretation

  • Conditions affecting red blood cell turnover (hemolytic anemia, recent blood transfusion, etc.) may cause discrepancies between A1C and true mean glycemia 2
  • Hemoglobin variants must be considered when A1C does not correlate with blood glucose monitoring levels 2
  • Racial/ethnic differences may exist in the relationship between A1C and average glucose, with some studies showing higher A1C values in African Americans compared to non-Hispanic whites for the same mean glucose concentration 2

Practical Application

  • Understanding the correlation between average blood glucose and A1C helps patients and providers better interpret glycemic control 3
  • While random blood glucose and estimated average glucose (eAG) derived from A1C show strong correlation in diabetic populations, they cannot be used interchangeably 4
  • For monitoring purposes, both A1C and blood glucose measurements provide complementary information about glycemic control 2

References

Guideline

A1C Value for Average Blood Sugar

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The correlation of hemoglobin A1c to blood glucose.

Journal of diabetes science and technology, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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