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- Hypercoagulable testing is almost never indicated or helpful in the acute/inpatient setting.
- Hypercoagulable testing should generally be reserved for patients with unprovoked and/or recurrent venous thromboembolism (VTE), a strong family history of VTE, age less than 45, clots in unusual locations, or history of warfarin-induced skin necrosis.
- Acute thrombosis can reduce antithrombin, protein C and protein S levels.
- Genetic tests can be ordered at the time of diagnosis, but almost never impact the initial management of an acute thrombotic event.
- Anticoagulants can affect the results of some assays. Heparin may cause a physiologic decrease in antithrombin levels and warfarin may reduce protein S and protein C levels. Anticoagulants may result in false positive lupus anticoagulant results. Do not order lupus anticoagulant/inhibitor testing if the patient is on a direct thrombin inhibitor (e.g. dabigatran, argatroban, or bivalirudin) or direct Xa innhibitor (e.g., rivaroxaban, apixaban, betrixaban or edoxaban) or fondaparinux. Direct thrombin inhibitors may cause a false elevation in the antithrombin in the assay used in this laboratory. Direct thrombin inhibitors and direct Xa inhibitors may cause a false negative of the activated protein C resistance ratio.
- There are other tests that MAY be indicated as part of a hypercoagulable workup, but such testing should only be done after consultation with Hematology.
Standard Testing for Genetic Thrombophilia includes:
- Factor 2 Prothrombin and Factor 5 Leiden Mutation Analysis (order together or individually if one has already been completed)
- Protein C Chromogenic
- Protein S Antigen, Free
- Antithrombin III
- Also draw INR and PTT if not drawn previously
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Standard Testing for Acquired Thrombophilia includes:
- Lupus Panel (anticoagulant/inhibitor)
- Cardiolipin Antibody IgG and IgM
- Beta-2-Glycoprotein Antibodies IgG and IgM
- Also draw INR and PTT if not previously drawn
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