Introduced May 2011, updated September 2022
Who should have Thrombophilia Screening?
Thrombophilia screening may be of value in the following groups:
- Patients with a venous thrombosis at an early age (<45) who also have a strong first-degree family history (one or more family members) of proven thrombosis
- Patients with a venous thrombosis at any age who have a strong first-degree family history (one or more family members) of unprovoked venous thrombosis.
- Patients with an unprovoked venous thrombosis at an early age (<45) with no family history should also be tested for antiphospholipid antibodies and lupus anticoagulant.
- Adults with skin necrosis in association with vitamin K antagonists, such as warfarin, should be tested for Protein C and Protein S deficiency once vitamin K antagonists have been withdrawn.
- Neonates and Children with Purpura Fulminans should be tested urgently for Protein C and Protein S deficiency and discussed with Haematology Consultant as further specialist assays may be needed.
- Case finding of asymptomatic relatives with high risk thrombophilia such as Antithrombin, Protein C and Protein S deficiency should only be considered in selected thrombosis prone families and only after the risks, benefits and limitations of testing have been discussed.
- Individuals with arterial thrombosis at a young age (<40) should be tested for acquired conditions such as antiphospholipid antibodies and lupus anticoagulant, and screening for myeloproliferative disorders should be considered
- Thrombosis in unusual sites (e.g. cerebral, mesenteric, portal – does NOT include retinal vein, upper limb or catheter-related VTE). Also consider screening for acquired myeloproliferative neoplasms in patients with portal or hepatic vein thrombosis as the prevalence of these conditions is high in this subgroup.
- Women with a history of recurrent miscarriage, pre-eclampsia intrauterine growth retardation eclampsia before 34 weeks of pregnancy or intrauterine death should be screened for the presence of antiphospholipid antibodies and lupus anticoagulant.
In all other situations testing should only be undertaken after consultation with a Haematologist or as part of a clinical trial.
Testing is not indicated in the following
- Case finding of asymptomatic relatives for the Factor V Leiden or Prothrombin Gene Mutations is not recommended.
- Thrombophilia screening should not be performed in asymptomatic patients considering use of oestrogen-based contraception. If these patients have a strong first-degree family history of thrombosis (one more family members), then alternative contraception (eg. Progesterone only pill, Progesterone depot injection / implant, intrauterine contraceptive devices) should be considered.
- Thrombophilia screening should not be performed in asymptomatic patients considering use of HRT. If these patients have a strong first-degree family history of thrombosis (one or more family members), then use of transdermal HRT should be considered as this represents a lower thrombotic risk.
- Thrombophilia screening should not be performed in asymptomatic patients planning pregnancy. If these patients have a strong first-degree family history of thrombosis (one or more family members) it may be appropriate to consider 6 weeks of post-partum thromboprophylaxis but this decision should be made on clinical grounds alone.
- Women who have suffered a VTE in a previous pregnancy or with use of oestrogen-based contraception may be given thromboprophylaxis in a subsequent pregnancy. This decision should be made on clinical grounds alone.
- Patients with central venous catheter related venous thrombosis or retinal vein occlusion
Timing of testing
- Screening at the time of acute thromboembolism is not indicated as the results are often misleading and will not influence initial management
- Thrombophilia screens should not be requested in patients on anticoagulants as both warfarin and heparin (and novel anticoagulants) may interfere with many of the tests.
- Thrombophilia screens should be performed once the patient has been off anticoagulant therapy for a least 3 weeks.
- Diagnosis of Antithrombin, Protein C or Protein S deficiency should not be made on a single abnormal result as a single test result may not be reliable.
- Pregnancy can influence the results of screening, therefore screening should be performed in the non-pregnant state.
- Where testing is indicated it is preferable for this to be done through the Thrombophilia Clinic to ensure that the correct tests are done including any necessary further specialist
Further information
A comment will appear on the test report when thrombophilia testing is not performed.
For thrombophilia testing requests beyond the clinical indications on this page please consult with a haematologist at Wellington SCL or Wellington Public Hospital.