[Measurements of the activity of the coagulation factors VIII:C, IX,XI, and XII in cats].

Using an optimized test, reference ranges were established for the activity of the coagulation factors VIII:C (72-124%), IX (81-130%), XI (69-134%) and XII (51-142%) in the cat (n = 58 cats, 2.5-97.5% quantile). Compared to a reference curve prepared by using a cat-pool plasma (n = 50), the factor VIII:C activity in humans (commercial human reference plasma) was 7.6%, i.e. the factor VIII:C activity in cats was 13 fold higher than in humans. The values for the factors IX, XI and XII depended distinctly on the dilution step of the human plasma. The activity of the cat in relation to humans was approximately 90% (factor IX), 170% (factor XI) and 135% (factor XII). Two clinically healthy cats who were conspicuous pre-operative because of a distinctly prolonged, activated partial thromboplastin time showed a decreased factor XII activity.