When should I consider referring a patient with iron deficiency anaemia for further investigation or specialist input?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 14 August 2025Updated: 14 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

You should consider referring a patient with iron deficiency anaemia for further investigation or specialist input in several specific circumstances:

  • Urgent Referral for Suspected Cancer:
    • Urgently refer people with iron deficiency anaemia using a suspected cancer pathway for colorectal cancer if they have a faecal immunochemical testing (FIT) result of at least 10 micrograms of haemoglobin per gram of faeces ,,.
    • For women aged over 55 years with postmenopausal bleeding, refer urgently using a suspected cancer pathway for an appointment within 2 weeks ,.
    • For women aged under 55 years with postmenopausal bleeding, consider referring urgently using a suspected cancer pathway for an appointment within 2 weeks ,.
  • Referral to Gastroenterology:
    • Refer 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 Hb levels may suggest more serious disease ,.
    • Refer all people aged 50 years or over with marked anaemia, or a significant family history of colorectal carcinoma, even if coeliac disease is found ,.
    • Refer premenopausal women (under 50 years) if they have colonic symptoms, a strong family history of gastrointestinal cancer (two affected first-degree relatives or one first-degree relative affected before age 50), persistent iron deficiency anaemia despite treatment, or if they do not menstruate (e.g., following hysterectomy) ,.
    • If coeliac serology is positive, refer to gastroenterology ,.
  • Referral to Gynaecology:
    • Refer women if menorrhagia is unresponsive to medical management ,.
    • Refer women if there is postmenopausal bleeding ,.
  • Referral to Obstetrics:
    • Refer pregnant women if there are significant symptoms and/or severe anaemia (haemoglobin less than 70 g/L), if pregnancy is at advanced gestation (over 34 weeks), or if there is failure to respond to a trial of oral iron ,.
  • Other Specialist Referrals:
    • Arrange referral if the person has profound anaemia with signs of heart failure ,.
    • Arrange referral if the person is unable to tolerate, or is not responding to, oral iron treatment ,.
    • Arrange referral if the person has initially responded to iron treatment but develops anaemia again without an obvious underlying cause ,.
    • Arrange referral when the type of anaemia is in doubt ,.
    • Arrange referral when further haematological investigations are required that cannot be carried out in primary care (such as bone marrow examination or an investigation of bleeding state) ,.

    It is important to note that treatment with iron replacement therapy should not be deferred while awaiting investigations for iron deficiency anaemia, unless colonoscopy is imminent ,.

Related Knowledge Topics

Educational content only. Always verify information and use clinical judgement.