Indicator Explainer
Hemoglobin A2
A tetrameric complex of 2 molecules of hemoglobin subunit alpha (encoded by either the HBA1 or HBA2 gene) and 2 molecules of hemoglobin subunit delta (encoded by the HBD gene).
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C172944. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-20. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
References
- NCI Thesaurus 26.09d — Hemoglobin A2 (C172944)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C172944. NCI definition, reproduced without modification under CC BY 4.0.
- Development of stabilizing hemoglobin A2 reference materials and assessment of commutability using multiple statistical models. — Anal Methods, 2026-07-23 (PMID 42333621; literature)
- Indirect determination of hemoglobin A2 reference intervals in Pakistani infants using data mining. — BMC Med Inform Decis Mak, 2025-01-09 (PMID 39789547; literature)
- A Variable Clinical Presentation of Hemoglobin City of Hope. — Clin Genet, 2024-12-18 (PMID 39696913; literature)
- Massive Splenomegaly in an Adult With a Hemoglobin Fractionation Pattern Suggestive of Hereditary Persistence of Fetal Hemoglobin: A Case Report. — Cureus, 2026-09-24 (PMID 42928811; literature)