White Blood Cell Count
The total number of infection-fighting white blood cells.
| Typical reference range | 3.8–10.8 x10E3/uL |
| Commonly cited optimal range | 4–7 x10E3/uL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
White blood cells are immune cells made in the bone marrow. The five main types are neutrophils, lymphocytes, monocytes, eosinophils and basophils, each reported in the differential.
Why it matters
WBC count screens for infection, inflammation, immune suppression and blood disorders. Within the normal range, persistently higher counts are associated with chronic low-grade inflammation and cardiovascular risk.
What a high result can mean
High counts commonly result from bacterial infection, inflammation, physical or emotional stress, smoking, corticosteroids, obesity and recent intense exercise. Very high or persistently unexplained counts can indicate leukemia or other marrow disorders.
What a low result can mean
Low counts can occur with viral infections, autoimmune disease, certain medications (chemotherapy, some antibiotics, antithyroid drugs), B12/folate deficiency and bone marrow problems. Mildly low counts are common and benign in some people, particularly those of African or Middle Eastern ancestry (benign ethnic neutropenia).
What affects the result
Counts vary through the day and rise with stress, exercise and smoking. Steroids raise neutrophils and lower lymphocytes and eosinophils. Always interpret the differential, especially absolute counts.
Units and conversion
Usually reported in x10E3/uL.
- From K/uL: multiply by 1 to get x10E3/uL
- From Thousand/uL: multiply by 1 to get x10E3/uL
- From 10^3/uL: multiply by 1 to get x10E3/uL
- From x10^9/L: multiply by 1 to get x10E3/uL
- From 10*3/uL: multiply by 1 to get x10E3/uL
- From x10E9/L: multiply by 1 to get x10E3/uL
- From G/L: multiply by 1 to get x10E3/uL
- From cells/uL: multiply by 0.001 to get x10E3/uL
Also called on lab reports
WBC, White Blood Cells, WBC Count, Leukocytes, White Cell Count, Leukocyte Count, Total WBC
Related tests: White Blood Cells & Differential
This page is educational and does not replace advice from a healthcare professional.