• Check ferritin
    • (beware falsely normal ferritin as also inflammatory marker)
    • If low – confirmed iron deficiency anaemia
      • Consider 2ww lower GI
        • Unexplained anaemia in men or non-menstruating women
        • FH – colorectal cancer in first degree relatives
      • History: Heavy periods, diet, urine dip, stool parasites
      • Investigate: Coeliacs serology (TTG)
      • Treat: Ferrous fumarate OD and increase as tolerated to BD + consider laxative – recheck Hb/Ferritin in 3 months
    • If normal/raised – consider anaemia of chronic disease or ferritin acting as acute phase reactant (in which case check serum iron/TIBC)
      • raised serum iron/TIBC and reduced transferrin saturation indicates iron deficiency
  • consider Hb electrophoresis
    • Beta Thalassaemia trait – raised HbA2
    • Alpha Thalassaemia trait – difficult diagnosis as no specific test
      • If confirmed, discuss with haematology as appropriate


Normal MCV

  • Consider
    • anaemia of chronic disease – chronic inflammation, endocrine, CKD, liver disease, malnutrition, MDS, haemochromatosis
    • mixed haematinic deficiency
    • recent blood loss
    • investigate as per raised MCV


Raised MCV

  • History: bleeding, diet, medications, alcohol, FHx, recent transfusion
  • Investigate: U+Es, LFTs+GGT, TFTs, B12, Folate, Blood film, Reticulocytes
  • Consider myeloma screen: serum/urine electrophoresis, immunoglobulins, bone profile
  • Refer to haematology if
    • abnormal cell shapes on blood film
    • persistent unexplained anaemia, raised MCV or B12 deficiency
    • spherocytes on blood film -> DAT + reticulocytes -> refer if raised



  • Abnormalities affecting more than one cell type (Hb, WCC, platelets) are more likely due to bone marrow causes. Consider early referral if the patient is unwell
  • Urgent referral to haematology
    • Leucoerythroblastic anaemia on blood film
    • Unexplained progressive symptomatic anaemia
    • Associated splenomegaly/lymphadenopathy or other cytopenias