Diagnostic significance of hemoglobin F and A2 levels in homo- and heterozygous beta-thalassemia during infancy.

For diagnosis of beta- and beta delta-thalassemia in the first year of life the physiological changes of hemoglobin F and A2 levels occurring in this age group have to be considered. The analysis of the hemoglobin pattern in 29 cases of thalassemia major and 285 cases of thalassemia trait, 47 of them aged less than one year, showed that all cases of homozygous beta-thalassemia aged less than one year could be diagnosed by definitely increased hemoglobin F levels exceeding the normal range for the appropriate age. In children older than ten years and in adults with heterozygous beta-thalassemia, the diagnosis could be made accurately by increased hemoglobin A2 levels in 97 percent. In children between one and ten years only 77 percent and in infants aged less than one year only 55 percent of the cases showed increases hemoglobin A2 levels. In contrast to adults, the hemoglobin F level seems to be helpful for the diagnosis of thalassemia trait. The younger the patient the more is the hemoglobin F level increased above the normal range for the appropriate age. It appears impossible to differentiate between beta- and beta delta-thalassemia trait when hemoglobin A2 is normal or low.