World Health Organization
Accurate determination of iron status is crucial for diagnostic and screening purposes in the clinical setting and to guide public health interventions at the population level. In an individual patient, diagnosis of iron deficiency or overload will help guide management, including further investigations and appropriate therapy. At the population level, determination of the magnitude and distribution of iron deficiency can help to prioritize appropriate interventions in settings in which the prevalence is regarded as a severe public health problem, or help to identify populations with hereditary conditions that predispose them to iron overload.
Ferritin is an iron-storage protein present in all cells and can be measured in serum, plasma, liver, red blood cells, and other specimens. Low ferritin concentrations suggest deficient iron stores, whereas elevated ferritin concentrations could suggest iron overload.