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Review
. 2021 Mar;21(2):107-113.
doi: 10.7861/clinmed.2020-0582.

Iron deficiency without anaemia: a diagnosis that matters

Abdulrahman Al-Naseem  1 , Abdelrahman Sallam  2 , Shamim Choudhury  2 , Jecko Thachil  3
Affiliations
Review

Iron deficiency without anaemia: a diagnosis that matters

Abdulrahman Al-Naseem et al. Clin Med (Lond). 2021 Mar.

Abstract

Iron deficiency anaemia (IDA) currently affects 1.2 billion people and iron deficiency without anaemia (IDWA) is at least twice as common. IDWA is poorly recognised by clinicians despite its high prevalence, probably because of suboptimal screening recommendations. Diagnosing IDWA relies on a combination of tests, including haemoglobin and ferritin levels, as well as transferrin saturation. Although the causes of iron deficiency may sometimes be obvious, many tend to be overlooked. Iron sufficiency throughout pregnancy is necessary for maternal and foetal health. Preoperative IDWA must be corrected to reduce the risk of transfusion and postoperative anaemia. Oral iron is the first-line treatment for managing IDWA; however, intravenous supplementation should be used in chronic inflammatory conditions and when oral therapy is poorly tolerated or ineffective. This review considers the causes and clinical features of IDWA, calls for greater awareness of the condition, and proposes diagnostic and management algorithms.

Keywords: anaemia; iron deficiency; pregnancy; preoperative; transfusion.

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Figures

Fig 1.
Fig 1.
An algorithm for the diagnosis of iron deficiency based on the best current evidence. This represents how tests are interpreted and not the order of requesting them. Hb = haemoglobin; ID = iron deficiency; IDWA = iron deficiency without anaemia; TSAT = transferrin saturation. *Normal levels of haemoglobin are ≥130 g/L for males, ≥120 g/L for females and ≥110 g/L for a pregnant female. **Ferritin levels below 30 μg/L indicate ID; in chronic inflammatory conditions ferritin levels may be elevated and so the threshold is raised to 100 μg/L. Ferritin levels can be raised to 100–300 μg/L in chronic inflammation; in such cases TSAT levels must be used. Normal ranges can slightly vary according to the laboratory.
Fig 2.
Fig 2.
Causes of iron deficiency. AI gastritis = autoimmune gastritis; anti H2 = anti histamine-2 receptor (H2 receptor antagonist); EPO = erythropoietin; GI cancers = gastrointestinal cancers; H pylori = Helicobacter pylori; IBD = inflammatory bowel disease; NSAIDs = non-steroidal anti-inflammatory drugs; PPIs = proton pump inhibitors; Tf = transferrin.
Fig 3.
Fig 3.
Effects of iron deficiency on the human body.
Fig 4.
Fig 4.
Flowchart summarising the management of iron deficiency without anaemia.,,
See this image and copyright information in PMC

Comment in

  • Iron deficiency without anaemia.
    Premjeyanth V, Shipman A. Premjeyanth V, et al. Clin Med (Lond). 2021 Jul;21(4):e427. doi: 10.7861/clinmed.Let.21.4.3. Clin Med (Lond). 2021. PMID: 35192494 Free PMC article. No abstract available.

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