Iron deficiency anaemia can be effectively diagnosed by a full blood examination and serum ferritin. Serum iron levels is not used to diagnose iron deficiency.
Anaemia is defined as a haemoglobin (Hb) concentration below the reference range for the laboratory performing the test. The World Health Organization (WHO) defines anaemia as a Hb level below 130 g/L in men, 120 g/L in non-pregnant women and 110 g/L in pregnant women and preschool children.
In an anaemic adult, a ferritin level below 15 μg/L is diagnostic of iron deficiency and levels between 15–30 μg/L are highly suggestive.
Ferritin is an acute phase reactant and is elevated in inflammation, infection, liver disease and malignancy. This can potentially lead to misleading results in patients who are iron deficient with co-existing systemic illness.
Iron deficiency is unlikely to be present with ferritin levels >100 μg/L, however functional iron deficiency may still need to be considered. See initial tests for further information.
Additional tests may be considered when the clinical features and haematology profile are suggestive of iron deficiency, but ferritin is normal. Consider consulting with a pathologist or haematologist before ordering these additional tests. Guidance may be required for results interpretation of additional tests of iron status where co-existing illness is present.
- Goddard AF, James MW, McIntyre AS, Scott BB on behalf of the British Society of Gastroenterology. Guidelines for the management of iron deficiency anaemia. Gut 2011;60:1309–1316. Available from: http://www.bsg.org.uk.
- Pasricha SR, Flecknoe-Brown SC, Allen KJ, Gibson PR, McMahon LP, Olynyk JK, et al. Diagnosis and management of iron deficiency anaemia: a clinical update. MJA 2010;193:525–532. Available from: http://www.mja.com.au.