Two cases are described of factor VII deficiency in the blood of healthy female beagles. The diagnosis was established on the basis of: (i) prolonged Quick's one-stage prothrombin and ‘Thrombotest’ times, both corrected by the addition of 10 per cent by volume of normal canine serum; (ii) normal Russell's viper venom time and thromboplastin generation test; and (iii) reduced factor VII activity compared with plasma from a normal dog. Attention is drawn to some implications of inherited blood-coagulation disorders not associated with physical evidence of bleeding.
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