Diagnosis

The diagnosis of folate deficiency anaemia is made by:

• clinical picture
  • often the cause is dietary - may be associated with other factors such as chronic disease, alcoholism, pregnancy
  • other causes include malabsorption, drugs, excessive utilisation of folate in malignancy, chronic well-compensated haemolysis (this may even occur with a normal haemoglobin level)
  • take a detailed history - consider causes noted above - diet, drugs, alcohol, symptoms of malabsorption
• diagnosis of megaloblastic anaemia:
  • FBC - macrocytic anaemia
  • a thrombocytopaenia may occur secondary to ineffective megakaryopoiesis
  • blood film - macrocytosis, hypersegmented neutrophils
  • bone marrow - megaloblastic erythropoiesis, giant metamyelocytes
• measurement of red cell folate levels; a good index of long term status as opposed to plasma folate levels which indicate recent nutritional status
• also measure serum B12 levels and absorption - the other main cause of megaloblastic macrocytic anaemia
• anti-gliadin and anti-endomysial antibodies - this may reveal subclinical coeliac disease
• liver function tests other haematinics - if not already undertaken - a useful assessment of nutritional status

Reference

1. Devalia V et al. The British Committee for Standards in Haematology. Guidelines for the diagnosis and treatment of cobalamin and folate disorders. Br J Haematol. 2014 Aug;166 (4):496-513