The estimation of fetal haemoglobin in healthy adults by radioimmunoassay.

A radioimmunoassay (RIA) for the measurement of fetal haemoglobin (HbF) was established and used to determine the distribution of HbF in 2463 British adults between the ages of 18 and 65 years. Although a range in HbF values was similar in both genders a shift towards higher values is seen in females and the mean HbF% is higher, in females, at all ages between 18 and 55. A significant and different fall in HbF over the age range studied was noted between females (47%) and males (23%). The difference in mean HbF between the genders was less marked after age 40 years and a small rise in HbF production was measured in females between ages 50 and 54 years.