A guantivitive radioimmunoassay of transferrin was established. Its antisera was obtained by immunizing rabbits with purified transferrin and the titer was as high as 1:6×104 with an affinity constant of 1.15×1012 l/mol. Ferrin

lactoferrin and serum aibimin showed no significant interference. The sensitivity was 2.54 ng/tube and the recovery was X =102.91%. The inter-batch CV was 1.8% （n = 14） and intra-batch CV was 9.94% （n=10）. The transferrin level （X±SD） of serum

urine and saliva in healthy adults measured by this method were 3.03±0.66 g/l （n = 31）

198±98 μg/l （n=55） and 557.89±206.32 μg/l （n=12） respectively. Serum transferrin in iron deficiency anemia were 6.46±4.15 g/l （n= 134）. 29 out of 35 cases of patients with abnormai. renal function had their urine transferrin higher than normal.