Hemoglobin F, Blood Clinical Information Discusses physiology,
pathophysiology, and general clinical aspects, as they relate to
a laboratory test Fetal hemoglobin concentration is usually
between 5% to 15% of the total hemoglobin in the high F or
delta/beta-type of thalassemia minor. In beta-thalassemia major,
fetal hemoglobin may be 30% to 90% or even more of the total
hemoglobin. Slight increases in hemoglobin F concentration are
found in a variety of unrelated hematologic disorders, such as
aplastic anemia, hereditary spherocytosis, and
myeloproliferative disorders. In homozygous sickle cell disease,
hemoglobin F concentration is often slightly increased. Higher
concentrations of hemoglobin F occur in hemoglobin S/beta
O-thalassemia, in patients who are doubly heterozygous for the
hemoglobin S gene, and in patients who have a gene for
hereditary persistence of fetal hemoglobin (HPFH). These
disorders may be differentiated by family studies or by flow
cytometry studies for fetal hemoglobin, which reveals un