White blood cell count (WBC): normal range and results
4,500–11,000 cells/µl; laboratory intervals differ; children's ranges are higher
- Updated
- 2026-09-10
- Every number with its source
What white blood cells are
White blood cells are produced in the bone marrow and are divided into five types, and an increase or a decrease in each of them means something different. That is why the total white blood cell count is only the beginning: a doctor looks at the differential white cell count — the percentage and the absolute number of each type — which is reported by the full blood count.
Reference range
| Group | Range, ×10⁹/l | Source |
|---|---|---|
| Adults 4,500–11,000 cells/µl; laboratory intervals differ; children's ranges are higher | 4.5–11.0 | MedlinePlus Reviewed 2025-02-03 |
The five types and what they point to
- Neutrophils (the most common) fight bacteria and rise with a bacterial infection, inflammation, stress and after steroids
- Lymphocytes act against viruses and rise in viral infections (mononucleosis) and in some blood diseases
- Monocytes rise in chronic infections and inflammation
- Eosinophils rise in allergies and parasitic infections
- Basophils — these rise only rarely
How to prepare
White blood cells fluctuate naturally through the day and rise after physical exertion, after eating, with stress, during pregnancy and in people who smoke; children's ranges are higher. A very high count without a clear infection, or a very low neutrophil count, calls for a more urgent assessment.
When the white blood cell count is tested
- As part of a full blood count — as a preventive check, before an operation, or during an illness
- When an infection is suspected — with a fever, or with signs of inflammation
- When an allergic reaction or a parasitic infection is suspected — the eosinophils are assessed
- To monitor treatment that affects the bone marrow — chemotherapy, certain medicines
- When blood diseases are suspected — leukaemia, lymphoma
- In autoimmune diseases
How to prepare
- No special preparation is usually needed
- Tell your doctor about any medicines you take — steroids, some antibiotics and others change white blood cell counts
- Intense physical exertion, stress and smoking before the test can raise the result temporarily
A raised white blood cell count
A raised white blood cell count (leukocytosis) most often points to an infection, especially a bacterial one, to an inflammatory disease, to tissue damage or to stress. Other causes are smoking, pregnancy, some medicines (steroids), the state after the spleen has been removed and, more rarely, leukaemia. Which type of white blood cell is raised points towards the cause.
- Infection — especially a bacterial one
- Inflammatory diseases
- Tissue damage — injury, burns, a heart attack
- Stress, intense physical exertion
- Smoking
- Pregnancy
- Medicines — steroids and others
- The state after the spleen has been removed
- Leukaemia — rarely; usually a very high count together with other changes
What to discuss with a doctor:
- The differential white cell count — which type is raised (neutrophils for bacteria, lymphocytes for viruses, eosinophils for allergy)
- CRP — whether there is inflammation
- Symptoms — fever, pain, a focus of infection
- Medicines taken, smoking
- A repeat test after recovery — white blood cells should return to the normal range
A low white blood cell count
A low white blood cell count (leukopenia) is most often linked to a viral infection, to certain medicines (chemotherapy, some antibiotics, medicines for the thyroid), to autoimmune diseases, to suppression of bone marrow function, to liver or spleen disease, or to severe infections. Some healthy people naturally have a lower white blood cell count. The most important thing is the neutrophil count: when it is very low, the risk of infection goes up.
- Viral infections — influenza, mononucleosis and others
- Medicines — chemotherapy, some antibiotics, medicines for the thyroid, others
- Autoimmune diseases — lupus, rheumatoid arthritis
- Suppression of bone marrow function, or bone marrow disease
- Liver or spleen disease
- Severe infections — sepsis
- Radiation
- Stress
- Inherited and ethnic variation — a naturally lower count without disease
What to discuss with a doctor:
- The differential white cell count — the absolute neutrophil number determines the risk of infection
- Whether you have recently had a viral infection — white blood cells fall temporarily
- Medicines taken
- A repeat test after a few weeks — whether the decrease persists
- If it persists with no explanation — other blood values, and the doctor's decision on further tests
About Lithuania
White blood cells with a differential count are part of the full blood count. At the Medicina practica laboratory in Lithuania that test costs from €10 (September 2026 pricing). When an infection is suspected, a family doctor orders it free of charge.
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal white blood cell count?
According to the MedlinePlus medical encyclopedia, the range for adults is 4.5–11.0×10⁹/l (4,500–11,000 cells/µl). Laboratory intervals differ, and children's ranges are higher.
›A white blood cell count of 12 — is that an infection?
A count of 12×10⁹/l is slightly above the range — most often that means an infection, inflammation or stress, but physical exertion, smoking and pregnancy also raise white blood cells temporarily. A doctor looks at the differential white cell count (which type is raised), at [CRP](/en/crp-test-explained) and at symptoms; with no symptoms, the test is usually repeated.
›A white blood cell count of 3.5 — is that dangerous?
A count of 3.5×10⁹/l is below the MedlinePlus range (4.5), but a small decrease is common after viral infections, and some healthy people have a count like that naturally. The most important thing is the absolute neutrophil number. A doctor usually repeats the test after a few weeks and reviews the medicines being taken.
›What is the differential white cell count?
It is the percentage and the absolute number of the five types of white blood cell — neutrophils, lymphocytes, monocytes, eosinophils and basophils. Neutrophils rise in bacterial infections, lymphocytes in viral ones, and eosinophils in allergies and parasitic infections. The differential says more than the total count.
›Do I need to fast before the test?
No. White blood cells are measured as part of a full blood count, with no special preparation. It is worth avoiding intense exercise and smoking before the test — they raise white blood cells temporarily.
›How much does a white blood cell count cost?
White blood cells with a differential count are included in the full blood count, which at the Medicina practica laboratory costs from €10 (September 2026 pricing). When an infection is suspected, a family doctor orders it free of charge.
Sources
- MedlinePlus Medical Encyclopedia: WBC count — 2026-09-06
- Medicina practica — 2026-09-06
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.