To diagnose folate-deficiency anaemia, your doctor will ask about your symptoms, examine you and may also ask about your medical history and ask you to have a blood test. Testing will include a full blood count(FBC) that shows the level of haemoglobin in your blood and how many of each of the different types of blood cell you have. A FBC test will also show the size of your red cells and the amount of haemoglobin in each one. Folate deficiency causes enlarged red blood cells, a condition called macrocytic anaemia. The level of folate in your blood can also be measured with the blood test. Your level of vitamin B12 will be checked too, because it's possible to have deficiencies of both vitamins at the same time.
Attribution: BUPA