Ferritin is anintracellular protein that stores iron and releases it in a controlled fashion. Itis found in most tissues, but small amounts are secreted into the serum where it functions as an iron carrier. Plasma ferritin is an indirect marker of the total amount of iron stored in the body.

Serum ferritin is used as a diagnostic test for iron-deficiency anaemiaand along with Iron studies as a screening test for haemochromatosis.

It should be noted it also behaves as an acute phase protein and can go upwith any pro- inflammatory processas well as kidney disease, liver disease and malignancy.

• Suspected iron deficiencyanaemia (the main reason for testing in primary care)
• Microcytic anaemia
• Non-anaemic pregnantwomenidentified asat risk of iron deficiency
• Poordiet/ intra-parenteral feeding
• Malabsorption syndromes
• Dialysis/ chronickidneydisease
• Erythropoiesis-stimulatingagents(ESAs)
  (usually secondary care)
• Investigation forpossiblehaemochromatosis
• Haemoglobinopathy where risk of iron loading (usually secondary care)

Repeat testing within 4 weeks of a result.

• To assess response to iron replacement in conjunction with full blood count. Typically after 3 months of replacement.
• Worsening symptoms with previous borderline result.
• Monitoring for specific patient groups such as haemochromatosis patients, haemoglobinopathy patients at risk of iron loading and dialysis patients would usually be undertaken by the relevant secondary care team.

1. Snook J, Bhala N, Beales ILP, Cannings D, Kightley C, Logan RP, et al. British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults. Gut. 2021 Nov 1;70(11):2030–51. Available at: https://gut.bmj.com/content/70/11/2030 DOI: 10.1136/gutjnl-2021-325210
2. Fletcher A, Forbes A, Svenson N, Wayne Thomas D, Paper and ABS for HGP. Guideline for the laboratory diagnosis of iron deficiency in adults (excluding pregnancy) and children. British Journal of Haematology. 2022;196(3):523–9. Available from: https://onlinelibrary.wiley.com/doi/10.1111/bjh.17900 DOI: 10.1111/bjh.17900
3. Pavord S, Daru J, Prasannan N, Robinson S, Stanworth S, Girling J, et al. UK guidelines on the management of iron deficiency in pregnancy. British Journal of Haematology. 2020;188(6):819–30. Available from:  https://onlinelibrary.wiley.com/doi/full/10.1111/bjh.16221 DOI: 10.1111/bjh.16221

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