Canterbury DHB


General Considerations and Causes

In the assessment of anaemia, factors to consider are:


< 80


  • Iron deficiency.
  • Anaemia of chronic inflammation.
  • Thalassemia.

80 to 100


  • Recent haemorrhage.
  • Renal failure.
  • Thyroid of other endocrine abnormality.

> 100


  • Alcohol excess.
  • B12/folate deficiency.

The anaemia may be primarily due to inadequate formation or excessive destruction, but remember acute blood loss. The main causes are listed in the following table.

Causes of Anaemia

Failure of production

Decreased erythropoietin production

  • Renal disease.
  • Starvation.
  • Endocrine deficiency states, e.g., hypothyroidism.

    Poor bone marrow response to erythropoietin

  • Iron deficiency, anaemia of chronic inflammation, sideroblastic anaemia.
  • B12/folate deficiency, marrow infiltration, MDS, leukaemias.

    Other conditions with reduced bone marrow red cell production

  • Congenital.
  • Pure red cell aplasia.
  • Aplastic anaemia.

Blood loss or excessive destruction

  • Acute bleeding.
  • Thalassaemia, abnormal haemoglobins.
  • Hereditary spherocytosis, elliptocytosis, pyropoikilocytosis.
  • Red cell enzyme deficiencies e.g. G6PD, PK.
  • Immune mediated red cell defects.
    • Auto immune haemolytic anaemia - idiopathic, secondary, warm, cold.
  • PNH.
  • Microangiopathic haemolytic anaemia.
  • Infections, burns, chemicals, drugs.

About this Canterbury DHB document (7933):

Document Owner:

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Last Reviewed:

November 2019

Next Review:

November 2022


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Topic Code: 7933