Complete blood count
White blood cells
White blood cells are your immune system’s workforce. The total count is a broad measure of immune activity, and the differential breaks it into the specific types.
Typical adult reference range
Roughly 4.0 to 11.0 · x10^9/L
Ranges vary between laboratories and by age, sex and method. Always read your own result against the range printed on your own report.
What a high result can mean
A high count most often reflects infection, inflammation, physical stress, or steroid medicines. It is a signal to look for a cause rather than a diagnosis in itself.
What a low result can mean
A low count can follow viral infections, some medicines including chemotherapy, autoimmune conditions, and B12 or folate deficiency. Some people, particularly of African ancestry, run a lower normal count with no health consequence at all.
What commonly affects this result
Recent or current infection, steroids, exercise and stress shortly before the draw, and time of day.
Questions worth asking your doctor
- Which type of white cell is driving this number?
- Could this simply be the infection I have just had?
- Is my count low enough to affect how we handle future illness?
See what your own results say
Upload your blood test and get a plain English summary of every value on it, with the questions worth raising at your next appointment.
Analyse my resultsThis page explains what a test measures. It is general information, not medical advice, and it cannot tell you what your own result means. Reference ranges differ between laboratories, and results are only meaningful alongside your history, your symptoms and your other results. Always discuss your results with your doctor.