Testing for anaemia and iron deficiency

When iron deficiency, with or without anaemia, is suspected, a combination of physical examination, medical history and diagnostic tests should be used to advance diagnosis. A physical examination can look for the signs and symptoms of iron deficiency. A review of the patient’s medical history could include1:

  • Nutritional history e.g. vegetarian/vegan diet2
  • Menstruation and pregnancy history1
  • Underlying conditions such as gastrointestinal diseases,3 chronic kidney disease,4 chronic heart failure,5 and cancer6
  • Medication use7
  • Family history of heredity diseases that can cause anaemia e.g. sickle cell anaemia and thalassemia
  • Hobbies/ activities, including extent of physical activity8
  • History of foreign travel to determine risk of exposure to parasitic disease, malaria or helminth diseases (parasitic worms)9

In addition to a medical history, diagnostic tests can be performed to confirm whether the patient is anaemic or not, and to investigate the underlying cause.

Testing for anaemia: The complete blood count

Performing a complete blood count (CBC) will indicate whether or not the patient is anaemic. The table provides the guideline values for multiple parameters measured in the CBC that are used to define anaemia. These values may differ depending on the age and gender of the patient.

Blood Test Men > 15 Years Old Women NonPregnant
> 15 Years Old
Women Pregnant
Hemoglobin (g/dL)3 < 13 < 12 < 11
Hematocrit(L/L)3 < 0.39 < 0.36 < 0.33
Red Blood Cell Count3,4 Normal range: 3600 - 5600 per mm3 Normal range: 4200 - 5800 per mm3
Mean Corpuscular Volume, MCV4 (Average red blood cell size; fL) < 80
Mean Corpuscular Haemoglobin, MCH4 (Average amount of haemoglobin within a red blood cell; pg) < 27

*The guideline values and the units provided in this table are for reference only. It is possible that the laboratory performing the analysis will use different guideline values or units. Other factors such as race and living altitude may also have to be taken into consideration.

Testing for iron deficiency

Blood tests that are specific for iron can confirm whether the patient is iron deficient and, if so, the extent of the iron deficiency. These tests include:

  • TSAT, or serum transferrin saturation12
  • Serum ferritin, a marker for iron storage1
  • Serum iron, the total amount of iron in the serum13
  • TIBC, or Total Iron-Binding Capacity13

The table below shows the values that may be used to confirm iron deficiency. 

Blood Test Result Guideline Values
Serum Ferritin < 12 µg/L for patients without co-existent inflammatory disease.8 If inflammatory disease is present, values of 50 µg/L may still be consistent with iron deficiency.8
Serum Iron < 60 µg/dL4
Total iron binding capacity (TIBC) > 410 µg/dL4
Transferrin saturation (TSAT) < 20%9

*The guideline values and the units provided in this table are for reference only and it is possible that the laboratory performing the analysis will use different guideline values or units.

If the patient is found to be iron deficient, the underlying cause of iron deficiency should also be investigated.

If the patient is anaemic but does not have iron deficiency anaemia, then additional causes of anaemia should be considered. These include:

  • Anaemia of chronic disease,16 associated with chronic inflammatory disorders, chronic infections and malignancy16
  • Haemolytic anaemia17
  • Anaemia due to vitamin B12 and/ or folic acid deficiency17
  • Renal anaemia,16 where the kidneys fail to produce sufficient erythropoietin18

Each patient requires treatment on an individual basis. There are multiple possible treatment options for iron deficiency anaemia.