Investigation and management of anaemia

The average lifespan of an erythrocyte is 120 days, and maintenance of a normal haemoglobin concentration requires the rate of production of erythroid cells to match the rate of loss from the circulation. Where this is insufficient, anaemia ensues. Deficiency of haematinics (iron, vitamin B₁₂, folate), bone marrow infiltration or chronic inflammation and organ dysfunction can result in impaired erythropoiesis. Abnormalities of the erythroid membrane, globin chains or intracellular enzymes shorten red cell lifespan, resulting in a congenital haemolytic anaemia. Acquired haemolysis is commonly immune or microangiopathic in aetiology. A detailed history including dietary, drug and family history, followed by interpretation of the full blood count, examination of the blood film and appropriate interpretation of simple tests (e.g. vitamin B₁₂, folate, ferritin) often identifies the cause of the anaemia. Multiple factors can contribute in patients who are older or have complex co-morbidities. Management of anaemia focuses primarily on treating the underlying cause. Blood transfusion is reserved for cases of acute-onset symptomatic anaemia and anaemia with no remedial cause.