Diagnosis of iron deficiency is not easily performed in inflammatory situation as usually encountered in elderly hospitalized patients (>70 years old). At first, we determined serum soluble receptor transferrin (RsTf), RsTf/serum ferritin ratio (RsTf-F index) and biochemical and haematological values used to evaluate iron status, in iron-depleted subjects (ferritinemia≤50 μg/L) (group 2) (n=22, 82±7 years) or not (group 1, reference group) (n=18, 82±6 years), without inflammatory diseases. Relevance of the biological parameters to diagnose iron deficiency was evaluated (ROC curve) and a cut-off value of RsTf-F (>1.85) was established. Then, we selected 60 patients (group 3) suspect of iron deficiency as previously validated with an inflammatory syndrome (CRP>12 mg/L). Almost all patients (95%) presented at least one risk factor of iron deficiency (anticoagulant drugs, nutritional or gastrointestinal diseases). In group 3, index RsTf-F values were increased (RsTf-F: 2.69±0.82 versus group 1: 1.25±0.34, p<0.05), in anemic patients (women Hb<120 g/L, men Hb<130 g/L) (n=42) and in non-anemic patients (n=18) (respectively RsTf-F: 2.84±0.87 versus 2.35±0.58, p<0.05). Thus, in elderly patients with inflammatory disorders, RsTf-F index could suspect iron deficiency before appearance of biological anemia.