Iron Deficiency Anaemia

General points

  • Please ensure the anaemia is iron deficient before referral to gastroenterology
  • Iron deficiency is defined by a low ferritin (biochemistry reports have reference values) and / or low Hb that responds to iron therapy
  • Ferritin maybe falsely raised so perform a CRP as well
  • The likelihood of a cause being found increases with age and the more severe the anaemia – consider this when deciding routine or urgent or 2 week wait referral
  • Dip the urine - 1% have renal tract carcinoma
  • Patients with normal Hb but a low ferritin should be referred if age 50 or over
  • Please perform a PR examination 

Definition of IDA

  • Anaemia by local laboratory values and
  • Ferritin < 15 ug/L
    • ferritin 15-30 ug/L with a normal CRP or 15-70 mg/L with a raised CRP is an equivocal result - it might be IDA and would warrant a trial of iron
    • ferritin > 30 ug/L with a normal CRP or >70 mg/L with a raised CRP is seldom IDA - if in doubt give trial of iron
  • or anaemia responding to iron therapy e.g. ferrous sulphate 200mg bd
    • Hb will increase by 1g/dl or more over 2 weeks if the patient is iron deficient 

Please refer:

  • All men and non-menstruating females
  • Menstruating females only need referral if they have
    • GI symptoms or
    • age 50 or over or
    • strong family history of GI cancer = one first degree relative diagnosed under age 45 or two affected first degree relatives 

Referral urgency:

  • Aged 50 or over with unexplained iron deficiency anaemia – refer via the 2ww colorectal service.

    Otherwise urgent or routine ERS referral depending on the likelihood of cancer (which increases with age and severity of anaemia)

Investigations prior to referral

  • FBC ferritin CRP
  • +/- response to iron
  • Coeliac serology (anti-TTG antibodies)
  • Urinalysis

However please don’t delay an urgent referral awaiting coeliac serology


  • give iron until Hb normalises and for 3 months thereafter
  • then watch FBC 3monthly for a year then yearly
  • please see clinical guidance map below for full details


  • If Hb or MCV drops give iron again as above
  • Further GI investigation is only necessary if the Hb cannot be maintained on iron


Upper GI red flags/2ww criteria: 

Refer for direct access gastroscopy:   

  • Dysphagia
  • Aged 55 or over with weight loss AND any of the following:
    • Reflux
    • Abdominal pain
    • Dyspepsia

Refer to the upper GI 2ww service: 

  • Ultrasound indicates gall bladder cancer
  • CT indicates pancreatic cancer
  • Ultrasound indicates pancreatic cancer
  • Upper abdominal mass consistent with gastric cancer
  • Any patient with jaundice
  • Aged 60 or over with weight loss AND any of the following:
    • Diarrhoea
    • Back pain
    • Abdominal pain
    • Nausea
    • Vomiting
    • Constipation
    • New onset diabetes

Lower GI cancer:




Clinical Knowledge Summaries (CKS). Anaemia – Iron Deficiency. Newcastle Upon Tyne: CKS; 2009.

British Society of Gastroenterology (BSG). Guidelines for the management of iron deficiency anaemia. London: BSG; 2005.