CBC (Complete Blood Count)
A group of blood tests that measure the number and size of the different cells in your blood.
CBC (Complete Blood Count)
A group of blood tests that measure the number and size of the different cells in your blood.
Also known as
- Complete blood count
- Full blood count
What it measures
- Red blood cells
- White blood cells
- Platelets
- Haemoglobin
- Haematocrit (the share of blood made up of red cells)
- Mean corpuscular volume (the average size of red cells)
Why a doctor may order it
Often part of a routine checkup. Doctors also use it to monitor a condition or treatment that may affect blood cell counts, such as infections, anaemia, immune system disorders and blood cancers.
What it helps evaluate
It can help doctors look for blood diseases, infections, immune system disorders and other conditions, and check for changes in an existing blood disorder.
Preparation
Usually no special preparation is needed.
Fasting
If other tests are being done on the same blood sample, you may be asked to fast for several hours. The lab or your doctor will tell you.
Important considerations
- There are many reasons a value can fall outside the usual range — for example, dehydration can change red-cell measurements — so a doctor looks at the whole picture.
Discuss results with your doctor
Talk to a doctor about your symptoms and about what your results mean — a single result is not a diagnosis. See a doctor promptly for severe or worsening symptoms.