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Adults with iron deficiency anaemia (IDA).
IDA is common and can be caused by a range of GI pathologies, including cancer. Approximately a third of men and postmenopausal women presenting with IDA have an underlying pathological abnormality, most commonly in the GI tract.
Level of risk of IDA for colorectal cancer
The World Health Organisation (WHO) defines anaemia as a haemoglobin (Hb) level two standard deviations below the normal for age and sex.
Iron deficiency should be confirmed by checking serum ferritin prior to investigation.
A serum ferritin level of less than 15 micrograms/L confirms iron deficiency.
Take a detailed medical history and ask about:
Include:
Iron deficiency anaemia is often multifactorial
Anaemia of chronic disease (ACD) is a common syndrome in which the anaemia is due to an inflammation-mediated reduction in red blood cell (RBC) production and sometimes in RBC survival. It is commonly found in acute and chronic infections; autoimmune disorders; chronic diseases; malignancy; after major trauma, surgery, or critical illness; and among older adults.
Laboratory studies typically show normocytic normochromic or microcytic hypochromic anaemia, relatively low absolute reticulocyte count, low serum iron, low total iron-binding capacity, low to normal percent transferrin saturation (TSAT), and elevated ferritin.
Please see Guidelines for the Management of Iron Deficiency Anaemia in Adults - The British Society of Gastroenterology (bsg.org.uk) for a complete differential diagnosis.
Thalassaemia and sideroblastic anaemia are both associated with an accumulation of iron, so tests will show an increase in serum ferritin and transferrin saturation (TSAT).
Unexplained IDA in all at-risk individuals is an accepted indication for fast-track secondary care referral in the UK because GI malignancies can present in this way, often in the absence of specific symptoms.
Red flags for lower GI cancer:
Recommended first line tests for investigation of suspected Iron Deficiency Anaemia table
Please note MCV may be normal in IDA and ferritin should be checked in all patients with anaemia.
Treat – replenish iron stores
Iron Replacement Therapy (IRT) should not be deferred while awaiting investigations for IDA unless colonoscopy is imminent.
If dietary deficiency of iron is thought to be a contributory cause of iron deficiency anaemia, advise the person to maintain an adequate balanced intake of iron-rich foods (for example dark green vegetables, iron-fortified bread, meat, apricots, prunes, and raisins) and consider referral to a dietitian.
Please see Iron (bda.uk.com) for further details.
Please refer to Section 9.1.1 Iron Deficiency Anaemias for Formulary guidance.
Parenteral iron should be considered when oral iron is contraindicated, ineffective or not tolerated. This is managed either via the appropriate specialist e.g. gastroenterology, gynaecology etc or your local community hospital – not via haematology (except in Plymouth).
Monitor - to ensure that there is an adequate response to iron treatment.
Patients should be monitored in the first 4 weeks for an Hb response to oral iron, and treatment should be continued for a period of around 3 months after normalisation of the Hb level, to ensure adequate repletion of the marrow iron store. Then monitor the person's full blood count periodically — for example, 3-monthly for 12 months and then 6-monthly for 2–3 years
Refer - where appropriate (see below)
Referral should be considered if the cause of iron deficiency is not clear or there is an inadequate response to iron treatment.
Prophylaxis – a prophylactic dose of iron may be beneficial in some people who have:
• Recurring anaemia (such as in an elderly person) and further investigations are not indicated or appropriate:
Ongoing prophylaxis may also be beneficial for:
Consider emergency admission under General Medicine for patients with:
Pregnant patients with Hb less than 70g/L – please contact duty Obstetrician if less than 20 weeks gestation, or duty Gynaecologist if 20 weeks and over
Urgently refer people with IDA on the Urgent Suspected Lower GI Cancer pathway if they are:
Please include Hb and ferritin taken within the last 4 weeks, and numerical result of FIT.
Please note iron deficiency is common in the elderly and is often multifactorial in aetiology. BSG recommends that the risks and benefits of invasive endoscopic and alternative investigation(s) are carefully considered in those with major comorbidities and/or limited performance status.
Consider an urgent referral for people with IDA on the Suspected Lower GI cancer pathway using a suspected cancer pathway if they are:
Please include Hb and ferritin taken within the last 4 weeks, and numerical result of FIT.
**Men with a haemoglobin (Hb) level less than 120 g/L and postmenopausal women with an Hb level less than 100 g/L should be investigated more urgently, as lower levels of Hb suggest more serious disease**.
Please note FIT is indicated in patients aged 60 or over with anaemia without iron deficiency (and urgent suspected cancer colorectal referral if positive)
Refer on Urgent Suspected Gynaecological Cancer pathway:
Refer urgently to Gynaecology and request urgent pelvic USS:
Please see Bleeding on HRT for full details on management of unscheduled bleeding on HRT
Pregnant patients with Hb less than 70g/L – please contact duty Obstetrician if less than 20 weeks gestation, or duty Gynaecologist if 20 weeks and over
Refer on Urgent Suspected Urological Cancer pathway:
Refer to nephrology:
Patients unable to tolerate, or not responding to, oral iron treatment
If the person is still unable to tolerate oral iron supplements, seek specialist advice. Please refer to the relevant specialty or local community hospital to consider parenteral iron.
Haematology Advice and Guidance may also be appropriate when:
Haematology Advice and Guidance is available in all localities
Please also see Anaemia in Adults guidance.
e-Referral Service Selection
Specialty: Haematology
Clinic Type: Not otherwise specified
Service: DRSS-Eastern-Haematology-Devon CCG- 15N
Pathway Group
This guideline has been signed off by NHS Devon
Publication date: July 24