Reference Interval:
Components Reference Interval
Hb A2 Age dependent - By Report
Hb F Age dependent - By Report
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| Interpretive Data: |
In laboratory confirmation of a β-thalassemia trait diagnosis, Hb A2 levels should be considered in conjunction with family history plus laboratory data, including serum iron and iron binding capacity, red cell morphology, hemoglobin, hematocrit, and mean corpuscular volume (MCV).
Please note that patients with the combination of iron deficiency and β-thalassemia may have a normal A2 level. An elevated A2 level cannot be used to screen for β-thalassemia in these cases.
| Patient State
| Hb A2 Level
| Hb F Level
| | Heterozygous β-thalassemia
| 4-9%
| 1-5%
| | Homozygous β-thalassemia
| Normal or Increased
| 80-100%
| | Heterozygous HPFH
| Less than 1.5%
| 10-20%
| | Homozygous HPFH
| Absent
| 100%
|
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| Note: |
Recommend quantitation of hemoglobin for definitive diagnosis after 1 year of age.
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| CPT Code(s): |
83021
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