Prolonged activated prothromboplastin time and breed specific variation in haemostatic analytes in healthy adult Bernese Mountain dogs

Coagulation tests are often performed in dogs suspected of haemostatic dysfunction and are interpreted according to validated laboratory reference intervals (RIs). Breed specific RIs for haematological and biochemical analytes have previously been identified in Bernese Mountain dogs, but it remains to be determined if breed specific RIs are necessary for haemostasis tests. Activated prothromboplastin time (aPTT), prothrombin time (PT), selected coagulation factors, D-dimers, fibrinogen, von Willebrand factor and thromboelastography (TEG) were analyzed in healthy Bernese Mountain dogs using the CLSI model.Three analytes (aPTT, TEG [MA] and TEG [G]) were different according to the CLSI model. For aPTT the new RI was markedly different (0–100 s). Whereas the new intervals for TEG (MA) and TEG (G) may be due to breed related biological variation, the cause of the prolonged RI for aPTT is at present uncertain.