[Assay of erythropoietin in plasma by enzyme-linked immunosorbent assay]

Using an enzyme linked immunosolvent assay kit supplied by Toyobo Co., erythropoietin (EPO) concentration in plasma was measured. Normal 100 samples showed a logarithmic distribution in EPO concentrations and normal range was between 5.4-32.5 mU/ml (mean +/- 2 SD). Coefficient variations (C.V.) of 3 samples continuously assayed were 3.8%, 6.5%, and 9.1% and C.V. of 3 samples assayed day by day were 3.6%, 7.2%, and 11.5%. Dilution test revealed that 3 samples diluted to 75%, 50%, and 25% were on each line which go through zero point. After the addition of 5.0, 15.0, and 35.0 mU/ml of EPO to the 3 samples, assay of EPO revealed 95.5 +/- 6.3% (mean +/- SD) of recovery. Assay of EPO in plasma from 19 patients with aplastic anemia revealed that all samples were higher than normal range and that 4 samples from the patients with severe aplastic anemia (less than 8.0 g/dl of hemoglobin) showed higher than 3,000 mU/ml. Furthermore, 67% (14/21) of samples from patients with leukemia showed higher than normal range in EPO concentration. EPO concentration in plasma from 17 patients with chronic renal failure were within normal range although the patients showed anemia.