Full blood count (FBC) – basics

The full blood count (also called FBC) test is a common blood test that provides important information about the 3 main types of cells in your blood:

• Red blood cells – containing haemoglobin that helps carry oxygen in your blood to other parts of your body.
• White blood cells – there are different types of white blood cells, that each work in a different way to help to fight infection. The cells types are neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
• Platelets – these are blood cells that help your blood clot, eg, after you are injured.

If you are healthy, without any symptoms, a FBC is not usually necessary as part of a routine check-up. It is normally used to help with the diagnosis and monitoring of different conditions and treatments. An FBC can be used to:

• diagnose anaemia
• help diagnose infection
• investigate a history of abnormal bleeding or clotting
• monitor the response to some types of medicines or radiation treatment
• help make sure that any planned major surgery will be safe.

Interpreting full blood count test results is complicated and is best done in consultation with your healthcare team. They will know what is normal for you and how these results relate to your other signs and symptoms. They are not perfect tests. Abnormal values can be found if you have other health conditions, not related to the blood.