Reviewed on : 26 Jan 2024

Reviewed by : Catherine Darby Senior Clinical Biochemist UHCW

Expires : 26 Jan 2026

Anaemia in Adults – Investigations and Management

Definition: Hb: Male <130g/l and female < 120g/l.

BUT:

Hb falls with age

Asymptomatic patient with Hb>110  above 65 years or a patient with Hb>100 above 75 years of age often does not require investigation.

Urgent referral to haematology:

• Blood film abnormalities ( refer if suggested by the Haematologist).
• Associated cytopenias ( platelets <80 and / or neutrophils <1.0).
• Lymphadenopathy or splenomegaly with anaemia.
• Unexplained, progressive or severe anaemia.

Useful questions to ask to aid investigation:

Is the cause likely to be Iron deficiency/bleeding?

• Bleeding history
• GI / Gynae / urological symptoms
• Low MCV
• Fall in MCV within normal range – check Ferritin, refer based on history (e.g. red flag for GI referral) Iron Malabsorption – PPI therapy, atrophic gastritis, known or suspected Coeliac or Crohn’s

Notes:

1. 1. Ferritin is an acute phase protein – Transferrin saturation useful if inflammatory symptoms and Ferritin normal / high.
2. 2. For patients with low MCV – have they had previous Hb electrophoresis? E.g. Alpha Thalassaemia trait is common and not clinically significant.

Is the cause likely NOT to be iron deficiency/bleeding?

MCV can help:

• Normocytic (80-100fl) Causes – CRF, chronic disease (inflammatory / cancer), myeloma, other haematological causes including myelodysplasia.
• Macrocytic (>100fl) Causes – B12 / Folate deficiency, alcohol / liver disease, hypothyroidism (rarely significant anaemia by itself) / myelodysplasia / haemolytic anaemia.

Note: B12 / Folate deficiency not usually referred – see B12 / Folate guidance.

Non-Urgent Referral to Haematology: 

• Symptomatic patients with unexplained anaemia (e.g. Hb 20g/L below their normal).
• Failure of response to oral iron (following appropriate investigation for cause of iron deficiency).
• Investigations prior to referral – Ferritin / transferrin saturation, B12/ Folate, renal and liver biochemistry, serum electrophoresis.

Management of Microcytic Anaemia (MCV <80f/l)

Consider iron deficiency.

• Ferritin <15µg/L and / or transferrin saturation <20%.
• A cause needs to be established for any case of iron deficiency.
• Patients with established iron deficiency anaemia usually treated initially with elemental iron e.g. ferrous sulphate 200mg bd.
• Advice to optimise absorption helps: take iron with a source of Vitamin C; avoid dairy products / tea / chapati flour.
• If patients are not responding to iron treatment, consider compliance issues and changing to a different oral preparation.
• PPIs inhibit iron absorption.
• Refer to Haematology to consider parental iron in patients with confirmed iron deficiency, that fail to respond to oral iron or those who are intolerant to at least 2 different oral preparations.

Once Hb is within normal range, iron supplementation needs to be continued for three months to build iron stores.

Anaemia Investigations Flowchart