Platelets (PLT)
Blood count (CBC) ·Also called: PLT, thrombocytes, platelet count, thrombocytopenia
What it is
Platelets are produced in the bone marrow and circulate for about a week. When a vessel is injured they stick to the site and to each other, forming the first temporary seal before the clotting proteins reinforce it.
Why your vet measures it
Spontaneous bleeding — pinpoint bruises on the gums or belly, nosebleeds, blood in urine — becomes a risk only when the count falls a long way below normal. Values modestly below the range rarely cause signs, and are often investigated for their cause rather than treated directly.
What a high result can mean
- A reactive response to inflammation, infection, or recent surgery
- Iron deficiency
- Removal of the spleen, or recovery after significant blood loss
- Rarely, a bone marrow disorder driving genuine overproduction
What a low result can mean
- Clumping in the sample tube, which the analyser cannot count — the most common cause of a low feline result
- Immune-mediated destruction, a well-recognised condition in dogs
- Tick-borne infections such as ehrlichiosis and anaplasmosis
- Consumption in widespread clotting (DIC), or bleeding from a vascular tumour
- Bone marrow disease or drug-related suppression
Dogs and cats differ
Feline platelets clump readily, so a low count on a cat's report is routinely rechecked on a smear before anyone acts on it. Cavalier King Charles Spaniels commonly carry an inherited macrothrombocytopenia: fewer but larger platelets, which analysers undercount, in dogs that clot perfectly well.
Questions worth asking your vet
- Was a blood smear checked for platelet clumping before we act on this?
- Is my pet's breed known for a benign low platelet count?
- Are there any signs of bleeding I should be watching for at home?
Related terms
See this value explained on your pet's own report
Upload the lab report or X-ray and get every value explained in the context of your own dog or cat — in minutes.
Explain my pet's results