[Comparison of indirect and direct measurement of transferrin in healthy and sick children (author's transl)].

In 207 children chemical measurement of total iron binding capacity (TIBC) and direct immunological evaluation of transferrin by radial immunodiffusion were compared. In addition, serum ferritin was measured in nearly all cases, to exclude iron deficiency. In 14 newborns, 20 infants and 35 older children TIBC and transferrin values correlated significantly (p < 0.001), as well as in various disorders (infections, hyporegenerative anemia, beta-thalassemia, acute blood loss) and in prelatent, latent and manifest iron deficiency. Standard deviations of both methods were comparable. Anemia and hyposideremia due to infection could be clearly distinguished from iron deficiency of all stages. The diagnosis of prelatent iron deficiency, however, can be definitely established only by measurement of serum ferritin or other more complicated procedures (59Fe2+-whole body retention test, estimation of diffuse iron in bone marrow macrophages). An interesting finding was the negative significant correlation (r = 0.69) between the two iron binding proteins in serum, transferrin and ferritin. In summary, the simple radial immunodiffusion technique for transferrin with its minimal requirement of serum can be recommended for pediatric routine laboratories in the differential diagnosis of anemia and hyposideremia, before unnecessary iron medication is institued.