Utility of screening for element V Leiden. opinion based on limited observational data.1,2 Package 1. Typical components of a thrombophilia blood panel Inherited claims em Heterozygous Element V Leiden mutation (FVR506Q) /em 6 Mutation in Element V gene confers resistance to activated protein C and raises thrombosis risk 3C5x em Heterozygous prothrombin VU 0357121 20210 mutation /em 7 Elevated prothrombin levels due to mutation increase risk by 2C3x em Heterozygous protein C deficiency /em 8 Rare mutations reduce the function or production of protein C, an inhibitor of coagulation together with protein S, increasing thrombosis risk around 3x em Heterozygous Rabbit Polyclonal to OR4K17 protein S deficiency /em 9 Rare mutations reducing function or production lead to improved risk of around 10x em Hereditary antithrombin deficiency /em 10 Reduced function or production of antithrombin thought to confer high thrombosis risk Dysfibrinogenaemia Very rare prothrombotic mutation thought to confer high thrombosis risk Acquired claims em Antiphospholipid antibodies (aPL) /em 3 Variable risk of venous or arterial thrombosis due to the presence of any one or a combination of anti-cardiolipin, lupus anticoagulant, or anti em /em 2-glycoprotein I antibodies. Antiphospholipid syndrome is due to the presence of prolonged aPL antibodies and/or particular pregnancy complications Full blood count, calcium, and liver function tests Variable risk of thrombosis due to the presence of malignancy or myeloproliferative disease The most common acquired thrombophilia state is definitely antiphospholipid antibodies (aPL), which requires positive tests for one or more of three antibodies on two occasions more than 12 weeks apart: lupus anticoagulant, anticardiolipin antibodies, and anti em /em 2-glycoprotein I antibodies. These are unusual in that they predispose to thrombosis in any vascular bed, so can cause arterial and microvascular events as well as venous thromboembolism (VTE).3 Pregnancy, malignancy, and some medicines produce prothrombotic claims, that underlie around 20% of instances of VTE,4 alongside myeloproliferative disease such as polycythaemia rubra vera. Dental and transdermal contraceptives, hormone alternative therapy, and tamoxifen are all associated with an increased risk of VTE, while pregnancy itself VU 0357121 causes a hypercoagulable state, in addition to improved venous stasis. More rarely, inflammatory claims such VU 0357121 as Beh?ets disease may underlie thrombosis. WHEN SHOULD I CONSIDER Screening FOR THROMBOPHILIA? As the recent Good guidelines emphasise, screening should only performed when it is likely to switch the patients management, such as in the riskCbenefit analysis of whether to discontinue anticoagulation after a recent VTE.1 Meta-analysis of prospective cohort and randomised controlled trials shows a very low risk of recurrent thrombosis in those with provoked VTE, in which case anticoagulation can safely be discontinued after 3 months for distal DVT, and 6 months for proximal DVT or PE.5 Conversely, if there is uncertainty in determining whether to stop anticoagulation after a case of unprovoked VTE (those circumstances where no temporary provoking risk factor such as hospital admission, pregnancy, or use of the combined oral contraceptive is recognized), the GP should consider aPL testing for acquired thrombophilia, as no positive family history is required to justify testing.1 The presence or absence of VTE in any first-degree relative should be sought and if present, inherited thrombophilia tests are indicated and in keeping with Good guidance.1 Testing for cancer is recommended by Good in individuals with unprovoked VTE, it may underlie 6C10% of all individuals with unprovoked VTE. Good suggests a physical exam, urinalysis, bloods (including full blood count, calcium, and liver function checks), and a chest X-ray should be performed. In those aged 40 years with non-diagnostic initial findings, an abdomino-pelvic CT should be offered, alongside a mammogram.
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