Neutrophils
Blood count (CBC) ·Also called: NEU, NEUT, segs, segmented neutrophils, bands, left shift
What it is
Neutrophils are short-lived cells that engulf bacteria and debris. Mature ones are called segmented neutrophils, or segs. Immature ones released early from the marrow are called bands, and a report noting bands is describing a left shift.
Why your vet measures it
The neutrophil count, and particularly whether bands are present, tells your vet how hard the body is fighting something. A high count with bands means active demand. A low count with bands is more worrying still — it suggests the marrow cannot keep up with what is being consumed.
What a high result can mean
- Bacterial infection — abscess, pyometra, pneumonia, infected wound
- Inflammation without infection, such as pancreatitis or immune-mediated disease
- Stress, illness, or steroid treatment, which shifts stored cells into circulation
- Some tumours, which drive a persistent inflammatory response
What a low result can mean
- Severe infection consuming neutrophils faster than they can be replaced
- Parvovirus in dogs and panleukopenia in cats, which attack the dividing cells in the marrow
- Chemotherapy or drug-related marrow suppression
- Immune-mediated destruction of neutrophils, which is uncommon
Dogs and cats differ
Dogs hold a larger reserve of mature neutrophils in the marrow than cats, so canine counts climb higher and faster in response to steroids or stress. A dog on prednisolone can easily double its neutrophil count with nothing else wrong.
Questions worth asking your vet
- Are there band neutrophils, and what does that tell us?
- Could steroids or stress explain a high count here?
- If the count is low, does my pet need protecting from infection right now?
Related terms
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