Dec 2021 QQ Summary: Thrombosis Risk Profile

Here is the summary of our December 2021 Quick Question, which drew 28 responses.
Question: The resident orders a thrombosis risk profile on an inpatient being treated for PE. How do you respond?

1. Run the profile but provide interpretation: 18% [5]
2. Recommend waiting until Rx is D/Ced: 68% [19]
3. Test for lupus anticoagulant only: 4% [1]
4. Perform molecular tests only: 10% [3]
5. Perform antigenic tests only: 0%
6. Run the profile as usual: 0%

In following the 10-19-2017 American Society for Clinical Pathology Choosing Wisely recommendation, anticoagulant therapy and inflammation are likely to interfere with the results of clot-based thrombosis risk assays such as activated protein C resistance, antithrombin, protein C, and protein S activity. Parallel quantitative [antigenic] test results are likewise compromised, as are the clot-based lupus anticoagulant assays, though anticardiolipin and anti-beta-2 glycoprotein 1 assays are valid. Consequently, the best practice is to avoid thrombosis risk testing in inpatients and to wait until at least two weeks after anticoagulant therapy is discontinued. Molecular tests for the factor V Leiden and prothrombin 20210 mutations may be used, as they are unaffected by inflammation. Attached is a 2019 PowerPoint slide listing a suggested thrombophilia profile.