Indicator Explainer
Hemoglobin S
A tetrameric complex of 2 molecules of hemoglobin subunit alpha (encoded by either the HBA1 or HBA2 gene) and 2 molecules of a hemoglobin subunit beta variant where the glutamic acid residue at position 7 has been replaced by valine.
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, C172950. 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 S (C172950)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C172950. NCI definition, reproduced without modification under CC BY 4.0.
- The sickling pressure index predicts hemoglobin S target achievement during chronic red cell exchange in sickle cell disease. — Transfusion, 2026-10-16 (PMID 42885580; literature)
- Epigenetic strategies for fetal hemoglobin induction in sickle cell disease. — Eur J Med Chem, 2026-08-03 (PMID 42551134; literature)
- Commentary on When Is Apparent Hemoglobin S Trait Something More Complex? — Clin Chem, 2026-08-01 (PMID 42545161; literature)
- Commentary on When Is Apparent Hemoglobin S Trait Something More Complex? — Clin Chem, 2026-08-01 (PMID 42545159; literature)
- When Is Apparent Hemoglobin S Trait Something More Complex? — Clin Chem, 2026-08-01 (PMID 42545158; literature)