modifies Increased Hemoglobin F SCDO:0000888 Persistence of Hemoglobin F Raised Hemoglobin F Increased Haemoglobin F Sufficient HP:0011904 http://purl.obolibrary.org/obo/HP_0011904 Hemoglobin F (HbF) contains two globin alpha chains and two globin gamma chains. It is the main form of hemoglobin in the fetus during the last seven months of intrauterine development and in the half year of postnatal life. In adults it normally makes up less than one percent of all hemoglobiin. This term refers to an increase in HbF above this limit. In beta thalassemia major, it may represent over 90 percent of all hemoglobin, and in beta thalassemia minor it may make up between 0.5 to 4 percent. Increased Hemoglobin Concentration Clinical Phenotype of Beta Thalassemia Phenotype of Sickle Cell Disease Altered Level of Normal Hemoglobin in SCD