What is B-Hb, fetal (HbF)?
B-Hb, fetal, also called HbF (fetal hemoglobin), is the type of hemoglobin that predominates in the fetus during pregnancy. After birth, HbF is gradually replaced by adult hemoglobin (HbA), and in healthy adults, only very small amounts of HbF remain – usually less than 1%.
When is the analysis of HbF important?
Measuring the level of HbF in the blood is particularly valuable in the investigation of various hereditary blood disorders, in particular:
- β-thalassemia and other thalassemias
- Sickle cell anemia (HbSS)
- Hereditary persistent fetal hemoglobin (HPFH)
- Myelodysplastic syndromes and certain leukemias
Elevated HbF in adults may be a sign that the body is compensating for defects in normal hemoglobin or that fetal production is retained in the genetic basis.
Included in the Hemoglobin Fractions test
The analysis of HbF is included as part of the broader laboratory test B-Hemoglobin Fractions, where other hemoglobin types such as HbA2, HbS and any unusual variants are also analyzed. Together, this provides an important basis for detecting and classifying hemoglobinopathies.
When should the test be considered?
HbF testing may be relevant in the following cases:
- Microcytic or normocytic anemia without a clear cause
- Suspected thalassemia major or sickle cell anemia
- Unclear blood status findings in newborns, children or adults
- Check for genetic investigations or hereditary conditions