Study sheds new light on bleeding risk in dogs with immune thrombocytopenia

12 November 2026

Platelet count alone may not predict clinically significant bleeding risk in dogs with immune thrombocytopenia, new research has found.

While dogs with severe thrombocytopenia are perceived to be at particular risk of spontaneous bleeding, the reasons for variability in bleeding tendency remain largely unknown.

A new study, carried out by researchers at the University of Glasgow and published in the Journal of Small Animal Practice, assessed risk factors for clinically significant bleeding in 159 dogs with severe thrombocytopenia (platelet count below 50 × 10⁹/L) presenting to a referral hospital.

Of the dogs included, 74 developed clinically significant bleeding and 84 had immune thrombocytopenia. Dogs with lower platelet counts were associated with clinically significant bleeding. However, this wasn’t the case with dogs within the immune thrombocytopenia subgroup, where platelet count was not a significant predictor of bleeding.

Increasing platelet count was associated with reduced odds of bleeding, with each increase of 10 × 10⁹/L in platelet count associated with a 28% reduction in the odds of clinically significant bleeding. Increasing monocyte count was associated with an increase in the risk of bleeding. Platelet indices, including plateletcrit, were not predictive of clinically significant bleeding. This adds to the evidence that platelet count alone does not give a full picture when assessing bleeding risk in dogs with immune thrombocytopenia.

The researchers suggest that inflammation might be a contributory factor in modulation of haemorrhagic risk and should be considered when evaluating bleeding risk in dogs with immune thrombocytopenia.

Dr George Smith, lead author of the study, said: “Our aim was to help frontline clinicians better predict serious bleeding in dogs with severe thrombocytopenia. Our findings highlight that platelet count alone does not reliably reflect bleeding risk in dogs with immune thrombocytopenia, emphasising the need for better ways to identify patients at greatest risk.”

Read the study in the Journal of Small Animal Practice.