See your GP if you experience symptoms of iron deficiency anaemia. A blood test will be able to confirm the diagnosis.
Your GP may also ask questions and carry out a physical examination to find the cause of your anaemia.
Blood test
To diagnose iron deficiency anaemia, a blood sample is taken from a vein in your arm and a full blood count is made. This means all the different types of blood cells in the sample will be measured.
If you have anaemia:
- your levels of haemoglobin (a protein that transports oxygen) will be lower than normal
- you will have fewer red blood cells (cells that contain haemoglobin) than normal
- your red blood cells may be smaller and paler than usual
Your GP may also test for a substance called ferritin, a protein that stores iron. If your ferritin levels are low, you do not have much iron stored in your body and may have iron deficiency anaemia.
Read more information about blood tests.
Vitamin B12 and folate
If your GP suspects your anaemia may be due to a vitamin B12 and folate deficiency, rather than an iron deficiency, your levels of these substances may be tested. Folate works with vitamin B12 to help your body produce red blood cells.
Vitamin B12 and folate deficiency anaemia is more common in people who are over 75 years of age.
Finding the cause
To determine the underlying cause of your anaemia, your GP may ask questions about your lifestyle and medical history. For example, you may be asked about:
- your diet - to see what you typically eat and whether this includes any iron-rich foods
- any medicines that you take - to see whether you have been regularly taking a type of medicine that can cause gastrointestinal bleeding (bleeding from the stomach and intestines), such as ibuprofen or aspirin
- your menstrual pattern - if you are a woman, your GP may ask if you have been experiencing particularly heavy periods (menorrhagia)
- your family history - you will be asked whether your immediate family has anaemia or a history of gastrointestinal bleeding or blood disorders
- blood donation - whether you regularly donate blood or have a history of excessive bleeding
- other medical conditions - your GP may ask whether you have recently had another illness or experienced other symptoms, such as weight loss
Physical examination
A physical examination will usually only be necessary if the cause for your iron deficiency anaemia has not been found.
Your GP may:
- examine your abdomen (stomach) as gastrointestinal bleeding is a common cause of anaemia
- look for signs of heart failure (when your heart is not pumping blood around your body very efficiently), such as swollen ankles, as the main symptom of heart failure is extreme tiredness
Two other possible types of physical examination you may have are explained below.
Rectal examination
A rectal examination is generally only necessary if there is rectal bleeding. This is a common procedure which can help your GP determine whether there is something in your gastrointestinal tract that may be causing bleeding. Your GP will insert a gloved, lubricated finger into your rectum so they can feel for abnormalities.
A rectal examination is not something to be embarrassed about as it is a procedure your GP will be used to performing. It should not cause significant pain or discomfort and you will only usually feel a slight sensation that your bowels are moving around.
Pelvic examination
Women may have a pelvic examination if their GP suspects heavy menstrual bleeding (menorrhagia) may be the cause of their anaemia.
During a pelvic examination, your GP will examine your vulva and labia (external sex organs) for signs of bleeding or infection. They may also examine you internally. This will involve your GP inserting gloved, lubricated fingers into your vagina to feel whether your ovaries and uterus (womb) are tender or enlarged.
A pelvic examination will not be carried out without your consent, and you will have the option of having someone with you during the procedure.
Pregnancy
Iron deficiency anaemia is common during pregnancy so your GP will only look for an alternative cause if your haemoglobin level is particularly low, or if your symptoms or medical history suggest your anaemia may be caused by something else.
Referral
Your GP may refer you to a gastroenterologist (a specialist in treating conditions of the digestive system), who will be able to carry out a more thorough examination, if:
- an abnormality was detected during a rectal examination
- you are anaemic and have experienced sudden or unexplained weight loss
- you are a woman who is not menstruating (having periods) and has a very low haemoglobin level
If you are a woman with heavy periods (menorrhagia), you may be referred to a gynaecologist if you fail to respond to treatment with iron supplements.
