Adjusting thresholds of serum ferritin for iron deficiency: a moving target☆

some studies, their use has limitations. For example, when ron deficiency anemia (IDA) is widely prevalent in patients of ll ages.1 In children and young adults, the diagnosis of IDA is ather straightforward. In elderly patients, however, the presnce of comorbidities usually hampers prompt diagnosis by onventional iron profile tests.2 When limited to conventional iron measures during evalations of suspected IDA in an elderly patient with a normal erritin level, transferring saturation becomes more reliable for iagnostic purposes. Comorbidity-related inflammation can ompromise the accuracy of iron tests, notably serum ferritin, hich is an acute phase reactant itself.2,3 Therefore, in order to scertain the diagnosis of IDA in elderly patients, it is advisable o take other iron parameters into account, such as transferrin aturation. Moreover, it is important to question what a ‘normal’ serum erritin level really is for this patient, since adoption of comonly used cut-off values (ranging from 15 to 30 ng/mL) to onfirm IDA would result in a large number of undiagnosed atients among the elderly.4 A distinction between absolute nd functional iron deficiency in this context is crucial. In bsolute iron deficiency, serum ferritin levels tend to mirror ow iron reserves unless falsely elevated due to inflammationelated conditions. On the other hand, a chronic inflammatory rocess is frequently associated with functional iron defiiency, a condition in which, in spite of satisfactory iron eserves with normal or even increased serum ferritin, the vailability of iron for the bone marrow is limited substantially ue to increased hepcidin transcription.5