From the Guidelines
The most appropriate time for a patient to see a hematologist for hypercoagulability workup after a DVT is typically after 3-6 months of anticoagulation therapy. This recommendation is based on the latest guidelines from the American Society of Hematology 2020 guidelines for management of venous thromboembolism: treatment of deep vein thrombosis and pulmonary embolism 1. Patients should remain on their prescribed anticoagulant (such as apixaban 5mg twice daily, rivaroxaban 20mg daily, warfarin with target INR 2-3, or enoxaparin) during this period.
The delay in testing is important because acute thrombosis and anticoagulation can affect test results, potentially leading to false positives or negatives. For example, protein C, protein S, and antithrombin levels may be temporarily decreased during acute clotting events or while on certain anticoagulants like warfarin 1. Similarly, factor levels and lupus anticoagulant testing can be affected by direct oral anticoagulants (DOACs). If testing is urgently needed before completing anticoagulation, it should be coordinated with the hematologist, who may recommend temporarily stopping anticoagulation if safe to do so.
Some key points to consider when evaluating the need for hypercoagulability workup include:
- Patients with strong family histories of thrombophilia
- Unusual clot locations
- Recurrent thrombosis
- Young patients (under 45) with unprovoked DVT These patients might benefit from earlier evaluation, as their risk of recurrence and potential for underlying thrombophilic conditions may be higher 1. However, for the majority of patients, waiting until after 3-6 months of anticoagulation therapy is the most appropriate approach to ensure accurate test results and guide further management.
From the Research
Hypercoagulability Workup after DVT
The decision to refer a patient to a hematologist for hypercoagulability workup after a deep vein thrombosis (DVT) depends on various factors, including the patient's clinical presentation, risk factors, and the presence of underlying conditions.
- The timing of the referral is not explicitly stated in the provided studies, but it can be inferred that hypercoagulability workup should be considered after the initial treatment of DVT, which typically lasts for 3-6 months 2.
- The studies suggest that testing for hypercoagulable states should be guided by the clinical presentation and suspected pathophysiology, and should only be pursued in patients with an increased risk for an underlying thrombophilia 3, 4.
- Patients with a history of recurrent VTE, family history of VTE, or underlying conditions such as cancer or antiphospholipid antibody syndrome may benefit from hypercoagulability workup 3, 4.
- The workup may involve evaluation of inherited and acquired thrombophilias, and may affect patient care by influencing the duration and type of anticoagulant therapy 3, 4.