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Test to Assess Clotting Status

From our ASCLS Consumer Web Forum: I was wondering if there is any test available to assess the clotting status of someone with factor V Leiden genetic disorder to verify if the treatment plan has been effective? If the patient has been on anticoagulants, is there a test to prove that the blood-clotting issue has been resolved or at least under control? Thanks for your help!

George’s response: Thank you for your provocative question. The short answer is no, there is no laboratory test to prove the patient’s thrombotic risk is resolved, or that the anticoagulant treatment is completely effective.

However, laboratory tests are able to show that an anticoagulant is within the effective therapeutic range. For instance, if the patient is being treated with Coumadin, we perform the PT/INR monthly to learn if the Coumadin dose is in the INR range of 2–3. Less than 2, the patient’s risk of a new thrombotic event rises, and over 3, the risk of bleeding rises. Of course, experience has shown that even people whose INR is a perfect 2.5 may occasionally experience a clot, illustrating that no drug is 100% effective. What we can say is that the patient’s risk is significantly reduced, and this is based on consistent findings in numerous clinical trials using thousands of patients.

The factor V Leiden mutation is permanent, so the patient will have the same elevated risk throughout life. The risk may rise or fall depending on lifestyle issues such as smoking and obesity, versus exercise, but it will always exist. There are a few acquired thrombotic risks, for instance, a common condition termed lupus anticoagulant, that may resolve over time. In those cases, the patient’s risk level returns to normal and is likely to remain normal unless the condition returns.

The question is provocative, and I’d like to see some enlightening participant responses.

Comments (1)
Anticoagulant Therapy
Vadim Kostousov
Oct 20, 2014 8:59am

I agree: we have so many inherited non-modifiable risk facto
I agree: we have so many inherited non-modifiable risk factors for thrombosis that heterozygous FV Leiden only marginally contributes to the thrombosis burden: among them non-O blood type and male gender are associated with an increased risk of primary venous thrombosis in population as well as thrombosis recurrence. Relevant recent reviews: (free full text)

D-dimer monitoring after anticoagulant treatment discontinuation helps to identify VTE patients with increased risk of recurrence (plus Related citations in PubMed:

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