Anaemia | Full Blood Count - MedSchool
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Full Blood Count
Full Blood Count
Anaemia is a very common condition that may occur in the context of reduced red blood cell production, increased red blood cell production, or red blood cell loss.




  • Anaemia is a very common condition that may occur in the context of reduced red blood cell production, increased red blood cell production, or red blood cell loss.
    • Look For

    • Reduced serum haemoglobin (Hb) concentration
    • Reduced haematocrit (HCT) / packed cell volume (PCV)
    • Reduced red cell count (RCC)
    • Causes of Anaemia

    • Reduced RBC Production

    • Haematinic deficiency - B12, folate, iron
    • Bone marrow pathology - aplastic anaemia, myeloproliferative diseases, myelofibrosis
    • Endocrine - EPO deficiency, hypothyroidism
    • Anaemia of chronic disease (infection / inflammation / malignancy)
    • Sideroblastic anaemia
    • Thalassaemias
    • Increased RBC Destruction (Haemolysis)

    • Immune haemolysis - autoimmune, alloimmune, drug-induced
    • Red cell fragmentation - thrombotic microangiopathies, mechanical haemolysis
    • Intrinsic RBC disorders - enzymopathies, membranopathies, haemoglobinopathies
    • Hypersplenism
    • Other - infection, copper, lead, hypophosphataemia
    • RBC Loss

    • Trauma
    • Gastrointestinal bleed
    • Bleeding from another source e.g. urinary tract
    • Factitious

    • Dilutional - excess fluid administration, pregnancy

Microcytic Hypochromic Anaemia

    • Look For

    • Low MCV (<80fL)
    • Low MCH / MCHC
    • Causes of Microcytic Hypochromic Anaemia

    • Normal RDW

    • Anaemia of chronic disease
    • Thalassaemia
    • Lead poisoning
    • Hyperthyroidism
    • Elevated RDW

    • Iron deficiency anaemia
    • Congenital sideroblastic anaemia

Normocytic Normochromic Anaemia

    • Look For

    • Normal MCV (80 - 100fL)
    • Normal MCH / MCHC
    • Causes of Normocytic Normochromic Anaemia

    • Normal RDW

    • Dilutional - excess fluid administration, pregnancy
    • Acute haemorrhage
    • Chronic kidney disease
    • Anaemia of chronic disease (infection / inflammation / malignancy)
    • Bone marrow infiltration - aplastic anaemia, myeloproliferative diseases, myelofibrosis
    • Elevated RDW

    • Early megaloblastic anaemia
    • Early iron deficiency anaemia
    • Haemolytic anaemia
    • Congenital sideroblastic anaemia

Macrocytic Hyperchromic Anaemia

    • Look For

    • Elevated MCV (>100fL)
    • Elevated MCH / MCHC
    • Causes of Macrocytic Hyperchromic Anaemia

    • Normal RDW

    • Aplastic anaemia
    • Post splenectomy
    • Hypothyroidism
    • Elevated RDW

    • Megaloblastic anaemia - B12 / folate deficiency, drugs
    • Myelodysplastic syndrome
    • Chronic liver disease

Macrocytic Hypochromic Anaemia

    • Look For

    • Elevated MCV (>100fL)
    • Low MCH / MCHC
    • Significance

    • Indicative of reticulocytosis.
    • Causes of Reticulocytosis

    • Haemolytic anaemia
    • Haemorrhage (acute or chronic)
    • Recovery post bone marrow suppression
    • Late pregnancy
    • High altitude
Last updated on October 13th, 2019


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