Platelets

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Platelets (thrombocytes) are clear, disc-shaped cells which are part of the line of white blood cells. Platelets are a vital part of the clotting mechanism of the blood system. When tissue damage occurs, platelets are activated by clotting factors to form a clump or aggregation to stop bleeding. After forming the blood clot, the platelets then secrete chemicals to promote fibroblasts to come & repair the tissue damage.

Platelets have a lifespan of about 6 days in dogs.

Normal platelet counts in dogs are between 200-500 x 10*9/l, but this varies according to breed. Sight hounds such as greyhounds can have a “low” platelet count which is actually quite normal for those breeds.

Low platelet levels (thrombocytopenia) can be extremely dangerous. Spontaneous bleeding can occur if platelet levels fall to 30-50 x 10*9/l. Platelet transfusions may be necessary for low counts.

High platelet levels (thrombocytosis) of 1,000 x 10*9/l or above give rise to a clotting risk (thrombosis), although if the cause of the rise can be eliminated, the levels should quickly return to normal.

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