Serum immunoreactive erythropoietin in healthy normal children

To provide reference data for normal children, serum immunoreactive erythropoietin (siEp) was estimated by radioimmunoassay in samples from 130 healthy children, 57 girls and 73 boys, with ages between 1 month and 16 years. In 128 of the children the (geometric) mean siEp was 15.8 miu/ml (iu: international units) with 95% range (the range within which 95% of the observations are predicted to fall) 9.1-27.6 miu/ml. There was no relation between siEp and the variables haemoglobin (Hb), PCV, age and sex. There were two outliers, both girls, aged 9.5 and 9.8 years, in whom siEp was greater than 256 miu/ml. In both, Hb and PCV were normal and we are unable to account for these atypical findings. Estimates of siEp in the 128 children were not significantly different from those in 22 healthy adults investigated simultaneously (mean 16.2 miu/ml, with 95% range 11.2-23.3 miu/ml).