Full blood count and film analysis

ANAEMIA

 Normal Hb 140-170 males;120-150 females

 Normal MCV 78-100

 Mean corpuscular Hb (MCH) 25-35

 Mean corpuscular Hb concentration (MCHC) 32-36

 Red cell distribution width (RCW %) 11.5-14.5

 Reticulocytes (%) 0.5-2.5

Differential based on size

 Microcytic – TICS – Thalassaemia, iron deficiency, chronic disease, sideroblastic

 Normocytic – RACH– Renal, autoimmune, chronic renal failure, haemoglobinopathies

 Macrocytic – BLOOD – B12/liver/EtOH, Folate, Drugs

 Microcytic anaemia

• Red cell distribution width high
• Ferritin low = Iron deficiency
• Ferritin normal = Anaemia of chronic disease, sideroblastic (hereditary or lead poisoning)
• Red cell distribution width normal
• RBC count low = Anaemia of chronic disease, hypothyroidism, Vitamin C deficiency
• RBC count normal or high = Thalassaemia

Normocytic anaemia

• Reticulocyte count normal
• RDW normal = Anaemia of chronic disease or anaemia of renal insufficiency
• RDW high = Iron, Vit B12 or folate deficiency
• Reticulocyte count high
• Coombs test positive = Autoimmune anaemia
• Coombs test negative = Enzymopathies (e.g. G6PD deficiency), haemoglobinopathies, microangiopathic haemolysis

Macrocytic anaemia

• RDW high = Vitamin B12 or folate deficiency
• RDW normal = Alcohol abuse, liver disease, hypothyroidism, drug-induced, myelodysplastic syndromes
  

COOMBS’ TEST

 Direct Coombs

• Detects antibodies to RBC’s
• Positive in autoimmune haemolytic anaemia, transfusion reactions and some drug-induced haemolytic anaemia  Indirect Coombs
• Used to detect antibodies to sera
• Used in compatibility testing before transfusion NOT diagnosis of anaemia

SICKLE CELL

BLOOD FILM

 Anisocytosis – Inequality of red cell size. Most common in macrocytic anaemia

 Poikilocytosis – Irregular red cell shape. Indicates dyserythropoiesis

 Hypochromia – Low Hb content (classic iron deficiency)

 Target cells – Red cells with central loss of staining. Due to increased surface:volume ratio due to severe iron deficiency, liver disease, sickle cell disease, thalassaemia, post-splenectomy and HbC disease

 Burr cells – Mature red cells with spiky projections on surface. Seen in uraemia and red cell trauma

 Basophilic stippling – RNA granules in cytoplasm indicating damaged young red cells. Seen in severe anaemia, lead poisoning and thalassaemia

 Polychromasia – Small amount of RNA in cytoplasm of normal reticulocytes

 Howell-Jolly bodies – Occur post-splenectomy as remnant of nuclear material

 Schistocytes – Intravascular haemolysis, RBC fragmentation by shearing forces, DIC, TTP, prosthetic heart valve, post-splenectomy

 Spherocytes – Extravascular haemolysis, RBC phagocytosis by macrophages

 Tear drop cells – Seen in myelofibrosis and extramedullary haematopoiesis

 Heinz bodies – Areas of denatured Hb seen in drug-related haemolytic anaemia

BLOOD FILM – WHITE CELLS

 Toxic granulation – Lysosomal granules in neutrophils. More specific for bacterial infection than neutrophilia itself

 Band forms – Presence of neutrophils with unsegmented nuclei

 Metamyelocytes and myelocytes – Leukaemic process or severe sepsis premature release from marrow

NEUTROPHILIA

 Stress

 Sepsis

 Leukaemoid reactions

 Glucocorticoids

 Malignancy

 Vasculitis

NEUTROPAENIA

 Infection (esp. viral)

 Chemotherapy

 Clozapine

 Sulphonamides

 Beta-lactams

LYMPHOCYTOSIS

 Infection: Viral, TB, toxoplasmosis, syphilis

 Thyrotoxicosis

 Leukaemia

 Lymphoma

LYMPHOCYTOPAENIA

 Stress response

 Prior corticosteroid therapy

 Autoimmune disease (SLE)

 Infection: Viral, severe sepsis, TB, brucellosis, HIV, histoplasmosis, CMV

 Cytotoxic drugs

Irradiation

ATYPICAL LYMPHOCYTES

 Viral infections: EBV, CMV, HIV

 Toxoplasmosis

 Leukaemia  Lymphoma

 Lead poisoning

Drug hypersensitivity

MONOCYTOSIS

 TB

 Leukaemia  Lymphoma

 Myelodysplasia

 IBD

Convalscence of any infection

EOSINOPHILIA

 Allergy

 Addisons

 Parasitic infection

 Sarcoidosis

 PAN

 Leukaemia

 Lymphoma

 Melanoma

 Irradiation

BASOPHILIA

 Infection: Viral, TB

 Hypothyroidism

 IBD

 Post-splenectomy

 Leukaemia

 Systemic mastocytosis

 Haemolysis

 Polycythaemia rubra vera

PANCYTOPAENIA

 Reduced marrow production ! Replacement of marrow (malignancy)

• Idiosyncratic drug reaction e.g. sulphonamides, phenytoin, carbamazepine, chloramphenicol
• Megaloblastic haematopoiesis (b12 deficiency)
• Autoantibodies (SLE)
• Myelofibrosis
• Myelodysplasia
• Cytotoxic agents
• Overwhelming infection

 Increased peripheral cell destruction

• SLE
• HIV
• Hypersplenism
• Paroxysmal nocturnal haemoglobinuria

THROMBOCYTOPAENIA

 Decreased production

• Pernicious anaemia
• Bone marrow failure  Increased destruction
• Sepsis
• HITTS
• ITP
• TTP
• HUS
• Intravascular device
• Drug-induced (antibiotics, thiazides, histamine antagonists)
• Antiphospholipid syndrome
• DIC
• HELLP
• Haemolysis

Last Updated on September 27, 2021 by Andrew Crofton