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Hemoglobin A1C

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Hemoglobin A1C, Glycosylated Hemoglobin, HBA1C, HgbA1c

  • Epidemiology
  1. Hemoglobin A1C may be important measure in non-diabetic
  2. Hemoglobin A1C associated mortality (contrast with <5)
    1. Relative Risk of Hemoglobin A1C 5.0 to 5.4
      1. All cause mortality: 1.41
      2. Cardiovascular mortality: 2.53
    2. Relative Risk of Hemoglobin A1C 5.4 to 6.9
      1. All cause mortality: 2.07
      2. Cardiovascular mortality: 2.46
    3. Relative Risk of Hemoglobin A1C 7.0 or higher
      1. All cause mortality: 2.64
      2. Cardiovascular mortality: 5.04
    4. References
      1. Khaw (2001) BMJ 322:15-8 [PubMed]
  • Background
  1. Glycosylated Hemoglobin is not equivalent to A1C
    1. Hemoglobin A1C is 70% total Glycosylated Hemoglobin
  • Causes
  • Falsely lower Hemoglobin A1C
  1. Acute blood loss
  2. Chronic Liver Disease
  3. Hemolytic Anemia
  4. HIV Antiretrovirals
  5. Pregnancy
  6. Vitamin E supplementation
  7. Vitamin C supplementation
  • Causes
  • Falsely higher Hemoglobin A1C
  1. Aplastic Anemia
  2. Hyperbilirubinemia
  3. Hypertriglyceridemia
  4. Iron Deficiency Anemia
  5. Renal Failure
  6. Splenectomy
  • Causes
  • Falsely modified Hemoglobin A1C (variably affected)
  1. Hemoglobinopathy
  2. Malnutrition
  1. Hemoglobin A1C of 6% represents mean Glucose of 130
  2. Each 1% increase in A1C, Glucose increases 30
  1. Hemoglobin A1C: 5.5% represents mean Glucose of 100
  2. Hemoglobin A1C: 7.0% represents mean Glucose of 150
  3. Hemoglobin A1C: 8.0% represents mean Glucose of 180
  4. Hemoglobin A1C: 9.0% represents mean Glucose of 220
  5. Hemoglobin A1C: 10.0% represents mean Glucose of 250
  6. Hemoglobin A1C: 11.5% represents mean Glucose of 300
  7. Hemoglobin A1C: 13.0% represents mean Glucose of 350
  1. Hemoglobin A1C <7.3%:
    1. Postprandial Glucose: 30%
    2. Fasting Glucose: 70%
  2. Hemoglobin A1C 7.3-8.4%
    1. Postprandial Glucose: 50%
    2. Fasting Glucose: 50%
  3. Hemoglobin A1C 8.5-9.2%
    1. Postprandial Glucose: 55%
    2. Fasting Glucose: 45%
  4. Hemoglobin A1C 9.3-10.2%
    1. Postprandial Glucose: 60%
    2. Fasting Glucose: 40%
  5. Hemoglobin A1C >10.2%
    1. Postprandial Glucose: 70%
    2. Fasting Glucose: 30%
  6. References
    1. Monnler (2003) Diabetes Care 26:881-5 [PubMed]
  1. Hemoglobin A1C <5.2%: No Diabetes Mellitus
    1. Test Sensitivity: 100%
  2. Hemoglobin A1C >6.5%: Diabetes Mellitus
    1. Test Specificity: 100%
  • References
  1. Malkani (2011) Am J Med 124(5): 395-401 +PMID:21531226 [PubMed]
  2. Pippitt (2016) Am Fam Physician 93(2): 103-9 [PubMed]