Test to Assess Clotting Status

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.