By The Pawline veterinary teamVeterinary-reviewed by Alastair Greenway, BVM&S MRCVS · 25 July 2026
Reference range · 10³/µL
617
Reference
6–17
Direction
Both unusually high and low values carry meaning.
This is the conventional reference interval. Your pet’s own report may print a slightly different range — always read the value against that. Sign in to see your pet’s value on this strip.
The white cell count reflects the immune system's activity. Both high and low values matter, but the total is only the headline — the pattern across the differential (which types of white cell have changed) tells you far more than the number alone.
The white blood cell count (WBC) totals up the body's circulating immune cells — a mixed army of several cell types, each with a different job. Because it lumps them together, the total WBC is best read as a first flag that the immune system is reacting, with the real story living in the differential: the breakdown into neutrophils, lymphocytes, monocytes, eosinophils and basophils. A given total can be reached in very different ways, and which cells are driving it is what carries the meaning.
The white cell count sums a mixed army of immune cells. The differential — which types have changed — matters more than the total.
Reading a high result
A raised white count (leukocytosis) most often reflects the body responding to inflammation, infection or stress. The differential tells you which:
A rise in neutrophils typically accompanies bacterial infection, inflammation, or the effect of stress and steroids.
A rise in lymphocytes can follow certain chronic stimulations or, when marked and persistent, raise the question of a lymphoid disorder.
Eosinophils climbing points towards parasites or allergic/inflammatory conditions.
A very high count, or one dominated by abnormal-looking cells, can indicate leukaemia and warrants urgent further testing. Everyday stress alone — a fractious cat, a frightened dog — can lift the count modestly, so context matters.
Reading a low result
A low white count (leukopenia) can be more concerning than a high one, because it may mean the immune army is being consumed faster than it is made (an overwhelming infection), or not being produced (bone-marrow suppression from certain viruses, drugs or disease). A low count, particularly a low neutrophil count, can leave a pet vulnerable to infection and usually prompts a prompt search for the cause.
In chronic disease
Tracked over time, the white count and its differential help follow inflammatory, infectious and immune conditions, and monitor the marrow-related effects of some treatments. Serial counts reveal whether an immune response is escalating or settling, and whether a therapy is suppressing the marrow — patterns a single count cannot show.
Cat vs dog
The white count is interpreted the same way in both species, with slightly different reference ranges. Stress shifts the count in characteristic ways in each — a classic "stress leukogram" (raised neutrophils and monocytes, lowered lymphocytes and eosinophils) is common in both dogs and cats and must be told apart from a genuine inflammatory response, which is exactly why the differential is read alongside the total.
How it's measured
The white count is measured as part of a complete blood count (CBC), reported in cells ×10³/µL (or ×10⁹/L). Modern analysers also produce the differential automatically, and a blood smear is examined when the cells need a closer look (for abnormal forms or to confirm the machine's count). Read the value, and the differential, against your own report's ranges.
What to do next
Because the total is only a headline, the useful next step when the white count is abnormal is to read the differential beneath it with your vet, and to weigh in stress. A pattern that fits infection, a marked or abnormal rise suggesting a marrow disorder, or a worrying low count each point to a different next test — which is why the breakdown, not the number, drives the plan.
Reference ranges reflect conventional laboratory intervals. Always interpret against your own lab's printed range and your veterinary surgeon's judgement. A brighter optimal band is shown only where a published guideline defines one, and it is cited.
This page is educational and is not a diagnosis. Lab results are interpreted in the full clinical context by your veterinary surgeon; a single value rarely tells the whole story.
