The assessment of frequency of iron deficiency in athletes from the transferrin receptor-ferritin index.

The transferrin receptor-ferritin index (sTfR/logFerr) was determined in 131 male and 121 female athletes in order to assess the frequency of iron deficiency (threshold value of that index taken as 1.8). Blood was drawn for determining morphological indices as well as sTfR, ferritin, iron, total iron binding capacity (TIBC), and haptoglobin. A significantly (p <.01) higher incidence of iron deficiency was observed in women (26%) than in men (11%). The iron deficiency was latent, since no subject was found to be anemic. The plasma iron was significantly lower and TIBC higher (p <.001) in both iron-deficient subgroups than in the non-deficient ones. This confirmed the latent character of iron deficiency. Some hematological indices (Hb, MCH, MCHC, MCV) were significantly lower in iron-deficient female athletes than in male athletes, which suggested a more profound iron deficiency in the former. The sTfR/logFerr index might thus be useful in detecting iron deficiency in athletes, especially in those with erythropoiesis disorders, since physical loads may affect the widely used ferritin levels.