Abstract
Passovoy factor deficiency, a coagulation abnormality affecting the intrinsic coagulation system, was discovered in 5 Western Australian kindreds. The defect is inherited as an autosomal dominant and is associated with a clinical bleeding tendency characterized by easy bruising and undue blood loss following trauma such as dental extraction and tonsillectomy. Fresh frozen plasma appears to provide effective prophylaxis during surgery. The activated partial thromboplastin time (APTT) shows a prolongation which, in most patients, is of relatively slight degree, and this may be the reason for the paucity of reports in the literature. The discovery of 5 kindreds carrying the defect suggests that it may be relatively common in the Australian community and that care should be taken to identify and follow up minor grades of abnormality of the APTT where individuals suspected of having an inherited bleeding tendency are screened. A sample from one case was distributed, with a clinical history, to participants in the Royal College of Pathologists of Australasia 1980 Quality Assurance Programme in Haematology. Approximately one-third of 175 participants failed to detect the definite abnormality present.