Thrombophilia testing of asymptomatic relatives of patients with
a history of VTE has not been shown to reduce the incidence of VTE.
The annual risk of unprovoked thrombosis in affected family members
Case-finding of asymptomatic relatives with low risk
thrombophilias such as heterozygosity for FV Leiden or PGV is not
indicated. Screening for AT deficiency is warranted in family
members of individuals with AT deficiency.
If family history suggests a high degree of genetic penetrance it
may be informative to test symptomatic patients and their
asymptomatic relatives with a view to informing clinical management
at times of high thrombotic risk.
VTE has a clear familial component, independent of the presence or
absence of a known thrombophilia risk factor. In symptomatic
families negative thrombophilia test results may be falsely