🔬 Blood Film Interpretation
A blood film is a vital haematology tool. It provides direct visualisation of blood cell morphology, which helps classify anaemias, detect haemolysis, monitor infections, and identify systemic disease. Always interpret alongside FBC indices and clinical history.
🩸 Red Cell Findings
- Anisocytosis: Variation in RBC size. Seen in iron deficiency, B12/folate deficiency, MDS.
- Poikilocytosis: Variation in RBC shape. Spherocytes (HS/AIHA), sickle cells, target cells, etc.
- Macrocytosis: MCV >100 fL. B12/folate deficiency, alcohol, liver disease, hypothyroidism.
- Microcytosis: MCV <80 fL. Iron deficiency, thalassaemia, lead poisoning.
- Rouleaux: “Stack of coins” RBCs. Seen with ↑ plasma proteins (myeloma, chronic inflammation).
- Agglutination: Clumped RBCs. Cold agglutinin disease, autoimmune haemolysis.
- Spherocytes: Small, round RBCs without central pallor. HS, autoimmune haemolysis.
- Elliptocytes: Rod-shaped RBCs. Hereditary elliptocytosis, iron deficiency.
- Target Cells: Bullseye appearance. Thalassaemia, liver disease, HbC disease.
- Polychromasia: Large, blue-tinged immature RBCs. Reticulocytosis in bleeding/haemolysis.
- Howell–Jolly Bodies: Nuclear remnants. Post-splenectomy, hyposplenism.
- Heinz Bodies: Denatured Hb. G6PD deficiency, oxidative haemolysis.
- Burr Cells (Echinocytes): Regular spiky RBCs. Uraemia, hypothyroidism, artefact.
- Acanthocytes: Irregular spiky RBCs. Liver disease, abetalipoproteinaemia, malnutrition.
- Schistocytes: RBC fragments. DIC, TTP/HUS, prosthetic valves (⚠️ urgent red flag).
🦠 White Cell Findings
- Left Shift: Presence of immature WBCs (myelocytes, metamyelocytes). Seen in infection, stress, marrow infiltration.
- Right Shift: Hypersegmented neutrophils (>5 lobes). Classic in B12/folate deficiency (megaloblastic anaemia).
- Toxic Granulation: Prominent neutrophil granules. Severe bacterial infection, sepsis, inflammation.
📌 Summary
The blood film provides morphological details that guide diagnosis.
🔑 Approach systematically: RBC size → shape → inclusions → WBC morphology → platelets.
Always integrate with FBC indices (Hb, MCV, RDW) and patient context for accurate interpretation.
