A normal full blood count (FBC)
A full blood count has three main components:
- Haemoglobin (‘Hb’)
- 130-170 g/L for men
- 110-150 g/L for women
- White cell count (WC) = 4-11 x10^9/L (million per litre)
- Platelet count = 150-400 x10^9/L (million per litre).
Here is more information on these three components.
1. Haemoglobin (‘Hb’)
- For adults, normal Hb levels are:
- 130–170 g/L for men
- 110–150 g/L for women
- Note. So a Hb of 120 g/L is anaemia for a man, but not a woman
- The Hb reflects the number of red cells (which carry oxygen) in the blood – a higher number means more red cells
- A low haemoglobin means you have a low number of red cells and is called anaemia
- A high haemoglobin means a high number of red cells and is called polycythaemia.
2. White cell count (WC)
- For adults, a normal white count is 4-11 x10^9/L (million per litre)
- These cells fight infection (and cancer and foreign bodies inside you)
- If you have too many of them (called leucocytosis), it could be a sign of inflammation, infection, cancer or another medical condition
- If it’s low (called leucopenia), you could be at a higher risk for infection. A medication, a viral infection, or a bone marrow disease could also cause a low count.
Note. Black people often have a slightly low WC (3.5-3.9). This is not a disease.
3. Platelet count
- For adults, a normal platelet count is 150-400 x10^9/L (million per litre)
- These cells clot the blood
- A low number is called thrombocytopenia. A high number is called thrombocythaemia.
Normal ranges of other components of an adult FBC
- Mean cell volume (MCV; size of a typical red cell) = 80-95 fL. <80 is microcytic, >95 is macrocytic
- Mean cell haemoglobin (MCH; amount of Hb inside a typical red cell) = 27-32 pg
- Differential white count. There are five types of white blood cells: basophils, eosinophils, lymphocytes, monocytes, and neutrophils. This test shows how many of each kind you have:
- Neutrophils = 1.8-7.5 x10^9/L
- Lymphocytes = 1.0-4.0 x10^9/L
- Monocytes = 0.2-0.8 x10^9/L
- Eosinophils = 0.1-0.4 x10^9/L
- Basophils = 0.02-0.10 x10^9/L.
Note. Different laboratories/hospitals will have slightly different normal ranges.
