Woman holding a blood drop
Why are red blood cells important?

Red blood cells are produced by the bone marrow and have a life span of 120 days.

In healthy people, millions are released into the blood stream each day to replace the old ones. To produce new red blood cells the body needs key ingredients such as iron.

Red blood cells contain a protein called haemoglobin. All tissues need oxygen to survive and haemoglobin delivers oxygen from the lungs to all parts of the body. The haemoglobin levels needed for this to happen are different in adult men and women.

For men, the haemoglobin reference range (that is, the range considered normal) is 125–185 grams per litre (g/L) and for women it’s 115–165 g/L.

Variations in reference ranges may be seen depending on the laboratory that is testing the blood.

Lady holding a blue question mark
What are the symptoms of anaemia?

Anaemia reduces the amount of oxygen in the body. The most common symptoms of this include:

  • tiredness
  • lethargy
  • feeling faint
  • becoming easily breathless.

Less common symptoms include headaches, palpitations, altered taste and ringing in the ears.

Depending on what’s causing your anaemia, you may have other symptoms too.

What causes anaemia? 

illustration of a scientist holding a magnifying glass and leaning over in front of a large red blood drop

There are many possible causes of anaemia, however it generally occurs by either:   

  • increased loss of red cells due to blood loss (bleeding) or destruction of red cells (haemolysis) 
  • problems with red cell production, including low numbers of red cells or abnormal red cells.   

In all cases, your doctor will need to work out what’s causing the underlying problem. Some examples could include: 

Increased blood loss
  • bleeding from the stomach or bowel 
  • heavy periods or childbirth 
Destruction of red cells 
  • sickle cell anaemia 
  • artificial heart valves 
Decreased number of red cells 
  • iron deficiency  
  • other vitamin deficiency such as B12 or folate 
  • bone marrow and stem cell problems including blood cancer 
  • medical conditions such as chronic kidney disease 
Abnormal red cells 
  • thalassaemia 
  • hereditary shperocytosis 


Iron deficiency is a common cause of anaemia in Australia, and the reason for a lack of iron needs to be worked out by your doctor. 

illustration of a scientist standing in front of test tubes

Finding the cause of anaemia and treating it 

The first step is checking whether you actually have anaemia with a blood test. It measures both your number of red blood cells and your haemoglobin level. Often more blood tests such as iron studies, vitamin B12 and folate levels, and kidney function are included. 

You should always see your doctor if you have any symptoms of anaemia. Your doctor will assess your symptoms, investigate, and work out if you need any treatment. Sometimes the cause is easy to find, but in other cases more tests may be necessary. 

Treatment of anaemia depends on the cause. In many cases, it may be as simple as iron tablets prescribed by your doctor.

Genetic causes of anaemia

Two examples of genetic causes of anaemia are sickle cell anaemia and thalassaemia. 

Before she had a stem cell transplant, Mapalo needed monthly blood treatments to fight debilitating sickle cell anaemia.
Before she had a stem cell transplant, Mapalo needed monthly blood treatments to fight debilitating sickle cell anaemia.

Sickle cell anaemia

Sickle cell anaemia is a genetic blood disorder which causes the body to make abnormal haemoglobin.

This affects the shape of the red blood cells causing them to be crescent or sickle shaped, which makes them inflexible and ‘sticky’. They can get stuck in small blood vessels blocking the flow of blood, depriving the tissues of oxygen and causing pain and organ damage.

The sickle cells also don’t last as long in the circulation as normal red blood cells leading to ‘sickle cell anaemia’. Red cell transfusions increase the supply of oxygen carrying haemoglobin. 


Thalassaemia is one of the most common genetic blood disorders in the world. Haemoglobin production is abnormal, resulting in anaemia.

Red cell transfusions give a temporary supply of healthy red blood cells with normal haemoglobin levels, which improves oxygen delivery to the tissues in the body. 

You may also like

illustration of a doctor in a white coat with stethoscope
Avoid a transfusion

There are some things you can do to lower the chances of needing a transfusion.

Check out these tips
illustration of a woman holding red and yellow droplets in each hand
Types of transfusion

Not all transfusions are the same. Red cells, platelets and plasma all treat different conditions.

See what they are
illustration of a woman holding a red blood pack
Receiving a transfusion

Everything you need to know, from what ‘informed consent’ means through to your recovery.

See our transfusion guide