II. 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]

III. Background

  1. Glycosylated Hemoglobin is not equivalent to A1C
    1. Hemoglobin A1C is 70% total Glycosylated Hemoglobin

IV. 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

V. Causes: Falsely higher Hemoglobin A1C

VI. Causes: Falsely modified Hemoglobin A1C (variably affected)

VII. Interpretation: Approximating Serum Glucose from A1C

  1. Hemoglobin A1C of 6% represents mean Glucose of 130
  2. Each 1% increase in A1C, Glucose increases 30

VIII. Interpretation: Correlation to Mean Serum Glucose

  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

IX. Interpretation: Fasting vs post-prandial Hyperglycemia

  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]

X. Interpretation: Diagnosis of Diabetes Mellitus

  1. Hemoglobin A1C <5.2%: No Diabetes Mellitus
    1. Test Sensitivity: 100%
  2. Hemoglobin A1C >6.5%: Diabetes Mellitus
    1. Test Specificity: 100%

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Related Studies

Ontology: Hemoglobin, Glycosylated (C0017853)

Concepts Biologically Active Substance (T123) , Amino Acid, Peptide, or Protein (T116)
MSH D006442
SnomedCT 143080000, 165678002, 259689004
LNC MTHU020323
English Glycated Hemoglobins, Glycosylated Hemoglobin, Hemoglobin, Glycosylated, Hemoglobins, Glycated, glycosylated hemoglobin, glycosylate hemoglobin, glycosylate haemoglobin, glycosylated hemoglobins, glycated haemoglobin, glycosylated hb, glycated hemoglobin, glycosylated haemoglobin, hemoglobin glycated, Hemoglobin.glycated, Glycated haemoglobin, Glycated hemoglobin, Glycosylated Hb, Glycosylated haemoglobin, Glycosylated hemoglobin, Glycosylated hemoglobin (substance)
French Hémoglobine glyquée, Hémoglobine glycosylée, Glycohémoglobine
Czech glykosylovaný hemoglobin, glykovaný hemoglobin
Spanish glucohemoglobina (sustancia), glucohemoglobina

Ontology: Glycosylated hemoglobin A (C0019018)

Definition (MSH) Minor hemoglobin components of human erythrocytes designated A1a, A1b, and A1c. Hemoglobin A1c is most important since its sugar moiety is glucose covalently bound to the terminal amino acid of the beta chain. Since normal glycohemoglobin concentrations exclude marked blood glucose fluctuations over the preceding three to four weeks, the concentration of glycosylated hemoglobin A is a more reliable index of the blood sugar average over a long period of time.
Concepts Biologically Active Substance (T123) , Amino Acid, Peptide, or Protein (T116)
MSH D006442
SnomedCT 33601001, 103232008, 259689004
LNC LP16413-4, MTHU018890
English Glycohemoglobin A, Glycosylated Hemoglobin A, Hb A1, Hb A1a+b, Hb A1c, HbA1, Hemoglobin A(1), Hemoglobin A, Glycosylated, Glycosylated hemoglobin A, HBA GLYCOSYLATED, HBA 01, HEMOGLOBIN AA 01, HB AC 01, Haemoglobin A1c, HbA1c, HbA>1c<, Hemoglobin A1c, HbA<sub>1c</sub>, Hemoglobin A, Glycosylated [Chemical/Ingredient], hemoglobin a1c, hba1, hemoglobin a 1, glycosylated hemoglobin a, hb a1, hba1c, haemoglobin a1c, HbA<sub>1c</sub> (substance), HbA1c (substance), HbA>1c< (substance), HbA1 - Glycated haemoglobin, HbA1 - Glycated hemoglobin, Glycosylated haemoglobin A, Glycosylated hemoglobin A (substance)
Swedish Hemoglobin A, glykosylerat
Spanish HbA>1c< (sustancia), hemoglobina A1c, hemoglobina glicosilada A, HbA>1c<, HbA1c, HbA<sub>1c</sub>, HbA1c (sustancia), HbA<sub>1c</sub> (sustancia), hemoglobina glucosilada, hemoglobina glucosilada (sustancia), hemoglobina A glucosilada (sustancia), hemoglobina A glucosilada, Glucohemoglobina A, Hb A1c, HbA1, Hemoglobina A(1), Hemoglobina A Glicosilada, Hemoglobina A Glucosilada
Czech HbA1, hemoglobin A glykosylovaný, glykovaný hemoglobin HbA1, glykovaný hemoglobin HbA1c
Finnish Hemoglobiini A1c
French Hb A1, HbA1, Hémoglobine A(1), Hémoglobine A1c, Hb A1c, Hb A1a+b, Hémoglobine A glycosylée, Glycohémoglobine A, Hémoglobine glycosylée A1c, Hémoglobine A1
Italian Hb A1a+b, Emoglobina A(1), Hb A1c, HbA1, Glicoemoglobina A, Hb A1, Emoglobina A glicosilata
German HBA 01, HB AC 01, HÄMOGLOBIN A 01, Hb A1c, HbA1, Glycohämoglobin A, Glycosyliertes Hämoglobin A, Hämoglobin A(1), Hämoglobin A, glycosyliertes
Polish Glikohemoglobina A, Hemoglobina A glikowana, HbA1c, Hemoglobina glikowana HbA1c
Japanese HbA糖化, グリコシルヘモグロビンA, グリコシル化ヘモグロビンA, グリコヘモグロビンA, ヘモグロビンA1, 糖化血色素A, 血色素A-糖化, グリコヘモグロビン, ヘモグロビンA1c, 糖化HbA, 糖化ヘモグロビンA
Portuguese Glicohemoglobina A, Hb A1c, HbA1, Hemoglobina A(1), Hemoglobina A Glicosilada

Ontology: Hemoglobin A1c measurement (C0474680)

Concepts Laboratory Procedure (T059)
SnomedCT 166902009, 144176003, 43396009
CPT 83037, 83036
English a1c hemoglobin testing, hemoglobin a1c test, a1c hemoglobin test, Hemoglobin A1C level, Haemoglobin A1c level, Haemoglobin A1c level (procedure), Hemoglobin A1c level, Hemoglobin A1c Test, Haemoglobin A1c measurement, HbA1c - Haemoglobin A1c level, HbA1c - Hemoglobin A1c level, Hemoglobin A1c measurement (procedure), Hemoglobin A1c measurement
Spanish medición de hemoglobina A1c (procedimiento), medición de hemoglobina A1c