Referral

Iron Deficiency Anaemia

Scope

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

  • High risk – men, women older than 50 years, and non-menstruating women older than 40 years.
  • Medium risk – menstruating women younger than 50 years without rectal bleeding and when menstruation, dietary, or blood donation is unlikely to be the cause.
  • Low risk – menstruating women younger than 50 years without rectal bleeding and when menstruation, diet, or blood donation is the likely cause.

The World Health Organisation (WHO) defines anaemia as a haemoglobin (Hb) level two standard deviations below the normal for age and sex.

  • In men aged over 15 years — Hb below 130 g/L.
  • In non-pregnant women aged over 15 years — Hb below 120 g/L.

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.

Out of Scope

  • Other anaemias
  • Children
  • Pregnant women
Toggle all

History

Take a detailed medical history and ask about:

  • Symptoms of anaemia - if the anaemia is severe, ask about specific symptoms (for example angina, palpitations, ankle swelling, fatigue, light headedness or shortness of breath)
  • Diet (to identify poor iron intake)
  • Drug history (e.g., aspirin, NSAIDs, SSRIs, anticoagulant therapy, corticosteroids, long-term use of PPIs over 2 years)
  • A history of overt bleeding particularly rectal bleeding, haematuria, heavy bruising, or blood donation
  • Change in bowel habit
  • Weight loss
  • A family history of:
    • Iron deficiency anaemia (which may indicate inherited disorders of iron absorption)
    • Bleeding disorders and telangiectasia
    • Colorectal carcinoma
    • Haematological disorders (for example thalassaemia)
    • Gastrointestinal disorders
  • A family history of cancers that could be related to Lynch syndrome, including Uterine, Stomach, Liver and Kidney
  • Menstrual history, pregnancy, or breastfeeding (if appropriate)
  • Travel history (increased risk of hookworm in travellers to the tropics)

Examination

  • Pallor
  • Cardiovascular assessment (tachycardia, hypotension etc)
  • Abdominal examination
  • Rectal examination

Include:

  • Overt bleeding, e.g. rectal bleeding, haematuria or heavy bruising
  • Menstrual, e.g., menorrhagia
  • Gastrointestinal, e.g., colorectal cancer, gastric cancer, gastric ulceration, coeliac disease
  • Inadequate diet
  • Medications, e.g., aspirin, NSAIDs, SSRIs, anticoagulant therapy, corticosteroids, long-term use of PPIs over 2 years
  • Others, e.g., blood donation, familial diseases

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:

  • IDA in men and post-menopausal women or any age with another red flag
  • Unexplained rectal bleeding age over 50yrs or any age with another red flag
  • Change in bowel habit age over 60yrs or any age with another red flag
  • Weight loss age over 40yrs with abdominal pain or any age with another red flag
  • Abdominal pain age over 40yrs with weight loss or any age with another red flag

Recommended first line tests for investigation of suspected Iron Deficiency Anaemia table

To confirm iron deficiency:
  • Full blood count (FBC)
  • Serum ferritin - in all people with anaemia - serum ferritin less than 30mcg/L confirms low iron stores and less than 15mcg/l confirms iron deficiency
  • C-reactive protein (CRP) – ferritin may be spuriously raised in the presence of inflammation
  • Reticulocyte count (shows bone marrow response to anaemia)
  • If serum ferritin inconclusive, check serum transferrin (high in IDA and low/normal in anaemia of inflammation) and transferrin saturation (TSAT) ((Low TSAT suggests problems with iron utilisation, and in association with anaemia may still indicate a requirement for iron, but may not indicate a need to investigate for chronic blood loss)
  • Consider a diagnostic trial of iron replacement therapy if the diagnosis is in doubt (once coeliac disease excluded) and review within 4 weeks -
  • Hb rise of 10g/L within 2 weeks is highly suggestive of iron deficiency, even if the result of iron studies are equivocal.

Please note MCV may be normal in IDA and ferritin should be checked in all patients with anaemia.

To investigate causes of iron deficiency:
  • Screen for Coeliac disease with tTG (CD is found in 1-3% of cases of IDA)
  • FIT in all patients being considered for referral to a suspected lower GI cancer pathway, except for those with an anal mass or anal ulceration (please see Suspected lower GI cancer referral pathway for full details). Please note IDA impairs the sensitivity of FIT so please refer even if negative.
  • FIT is also indicated in patients aged 60 or over with anaemia without iron deficiency (and urgent suspected cancer colorectal referral if positive)
  • Check urine dip for haematuria

Treatment and monitoring

Please refer to Devon Formulary guidance:

9.1.1 Iron deficiency anaemias - North & East (devonformularyguidance.nhs.uk)

9.1.1 Iron-deficiency anaemias - South & West (devonformularyguidance.nhs.uk)

Refer - where appropriate (see below)

Emergency admission

Consider emergency admission under General Medicine for patients with:

  • cardiac decompensation due to anaemia – e.g., uncontrolled heart failure, or unstable angina
  • haemoglobin below 60g/L regardless of symptoms since decompensation can occur unpredictably below this level and close monitoring and transfusion may be indicated.
Pregnancy

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

Gastroenterology/Colorectal

Urgently refer people with IDA on the Urgent Suspected Lower GI Cancer pathway if they are:

  • Aged 60 years or over
  • Or any age with a faecal immunochemical testing (FIT) result of at least 10 micrograms of haemoglobin per gram of faeces.

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:

  • Aged under 50 years and present with rectal bleeding.

Please include Hb and ferritin taken within the last 4 weeks, and numerical result of FIT.

Refer to gastroenterology:
  • All men and postmenopausal women with iron deficiency anaemia unless they have overt non-gastrointestinal bleeding.

**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**.

  • All people aged 50 years or over with marked anaemia, or a significant family history of colorectal carcinoma, even if coeliac disease is found.
  • Premenopausal women if they are aged under 50 years and have colonic symptoms, a strong family history (two affected first-degree relatives or just one first-degree relative affected before the age of 50 years) of gastrointestinal cancer, persistent iron deficiency anaemia despite treatment, or if they do not menstruate (for example, following hysterectomy).
  • Positive coeliac serology

Please note FIT is indicated in patients aged 60 or over with anaemia without iron deficiency (and urgent suspected cancer colorectal referral if positive)

Gynaecology

Refer on Urgent Suspected Gynaecological Cancer pathway:

  • Aged 55 and over with post-menopausal bleeding (unexplained vaginal bleeding more than 12 months after menstruation has stopped because of the menopause)
  • Unscheduled bleeding on HRT with a family history of endometrial hyperplasia, endometrial cancer or Lynch syndrome
  • Unscheduled bleeding on HRT with a BMI of 40 and over
  • Unscheduled bleeding persisting after 6 months of starting or changing HRT
  • Unscheduled bleeding persisting more than 4 weeks after stopping HRT
  • Consider referral if aged under 55 with post-menopausal bleeding

Refer urgently to Gynaecology and request urgent pelvic USS:

  • IDA in association with heavy menstrual bleeding or irregular PV bleeding in women aged over 40yrs who are not pregnant and not post-menopausal (women with a raised BMI or type 2 diabetes or a history of PCOS have a greater background risk of endometrial hyperplasia and endometrial cancer, which can be associated with IDA)

Please see Bleeding on HRT for full details on management of unscheduled bleeding on HRT

Urology

Refer on Urgent Suspected Urological Cancer pathway:

  • Aged 45 and over with unexplained visible haematuria without urinary tract infection
  • Aged 60 and over with unexplained non-visible haematuria with dysuria or unexplained non-visible haematuria with a raised white cell count on a blood test
Nephrology

Refer to nephrology:

  • Haemoglobin less than 110 g/L and eGFR less than 45 ml/min/1.73 m² (non-renal causes should have been excluded)
Haematology
  • Consider Haematology referral or seek specialist advice via Haematology Advice and Guidance if there is a lack of response to oral iron.

Haematology Advice and Guidance is available in all localities

Haematology Advice and Guidance may also be appropriate when:

  • Iron deficiency anaemia is recurrent or progressive without an obvious underlying cause including B12 and folate deficiency and thyroid dysfunction
  • When the type of anaemia is in doubt

Haematology Advice and Guidance is available in all localities

Please also see Anaemia in Adults guidance.

  • If the person has already had normal upper and lower gastrointestinal investigations for iron deficiency anaemia and the anaemia persists or recurs, consider testing for Helicobacter pylori, and eradicate if present.

Please refer to the relevant specialty or local community hospital to consider parenteral iron.

Referral Instructions

e-Referral Service Selection

Specialty: Haematology

Clinic Type: Not otherwise specified

Service: DRSS-Eastern-Haematology-Devon CCG- 15N

Referral Form

DRSS Referral Form

Pathway Group

This guideline has been signed off by NHS Devon

Publication date: August 2024