Open a PDF version to print this topic

HealthInfo Waitaha Canterbury

Overview of anaemia

Tirohanga whānui ki te mate pūtau toto whero

In anaemia you have fewer red blood cellsAnaemia is when you do not have enough healthy red blood cells to carry the oxygen you need around your body. If you have anaemia, you may feel tired, light-headed and weak.

Your body has three main types of blood cells:

Red blood cells contain haemoglobin. This is an iron-rich protein that helps red blood cells carry oxygen from your lungs to your body’s tissues. Oxygen is needed to help your body function properly. To make red blood cells and haemoglobin, your body needs to get iron, vitamin B12, folate and other nutrients from the foods you eat.

Symptoms of anaemia

Common anaemia symptoms are due to having less oxygen in your body. They include:

Types of anaemia

Iron deficiency anaemia is the most common type. It occurs when your body does not have enough iron to produce haemoglobin. It is common in:

Pernicious anaemia or vitamin B12 deficiency anaemia occurs if your body cannot absorb enough vitamin B12 from food.

Folic acid deficiency anaemia can happen if you do not get enough folic acid from your food. This can happen with some gut conditions.

Aplastic anaemia occurs if your body cannot make enough red blood cells, white blood cells and platelets. It happens when there is damage to your bone marrow caused by things like:

Haemolytic anaemia occurs when your body destroys red blood cells and cannot replace them fast enough. It can:

Another common cause of anaemia is losing too much blood. This can happen because of:

Diagnosing anaemia

Anaemia is diagnosed by blood tests, mainly a full blood count. See your doctor if you think you have anaemia. Depending on the type of anaemia, you may need more tests to confirm the diagnosis and to check for any medical condition causing your anaemia.

Treating anaemia

Treating anaemia depends on the cause. If the anaemia is because you are not getting enough of the right nourishment, the treatment may be simple. For example, taking iron supplements for iron deficiency anaemia. Other causes of anaemia may be more complex, and the underlying cause must be treated.

If left untreated, anaemia can lead to an irregular heartbeat (called arrhythmias). Over time, arrhythmias can damage your heart and possibly lead to heart failure. Anaemia also can damage other organs in your body because your blood cannot get enough oxygen to them.

Written by HealthInfo clinical advisers. Last reviewed February 2023.


See also:

Folic acid deficiency anaemia

Low iron and iron deficiency anaemia

Low vitamin B12 and pernicious anaemia


Understanding your complete blood count results

Page reference: 281687

Review key: HIANA-16978