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Protein C and Protein S Deficiency

Here is a question I answered yesterday for the ASCLS Consumer Forum. It discusses a common problem, so I have reproduced it here: Should Lovenox be used for someone with a protein C and protein S deficiency when there is a coumadin hold related to a procedure scheduled?

My answer: Your physician may choose to double-check the diagnosis of protein C and protein S deficiency. The prevalence of protein C deficiency is 1 in 300 and protein S deficiency prevalence is unknown but is less frequent than 1 in 1,000, so the possibility of someone inheriting both deficiencies together is less than 1 in 300,000, extremely rare. We often make a fundamental error by testing for protein C and protein S deficiency when a patient is taking coumadin (warfarin), or when they have had a recent thrombotic event, both of which consistently cause both protein C and protein S to be temporarily decreased. To confirm protein C and protein S deficiency, the patient must be off coumadin for at least 14 days (a medical decision based on patient safety) and must not have an active clotting episode in progress. Most physicians like to further confirm the diagnosis by repeating the test after 12 weeks and also testing the patient’s first-degree relatives, especially as there are many instances in which protein C and protein S may be temporarily decreased, such as in inflammation or during pregnancy.

Aside from the issue of protein C and protein S deficiency, the patient you are describing may have had one or more thrombotic (blood clotting) episodes that are independent of the protein C and protein S diagnosis. In that instance, the patient must remain on some form of antithrombotic therapy to avoid a new adverse incident. The physician, surgeon, or dentist may choose to discontinue coumadin for a period of time and “bridge” with Lovenox before and shortly after the procedure. The medical standards for bridging therapy depend on the risk of additional thrombosis, the type of procedure, and the risk of bleeding during the procedure. Fortunately, the standard for therapy is carefully spelled out in the following article, which is available free online from the American College of Chest Physicians (ACCP) at

Douketis JD, Berger PB, Dunn AS, et al. The perioperative management of antithrombotic therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th edition). Chest 2008;133:299S-340S.

The ACCP guidelines are international medical practice standards that surgeons, dentists, and internists treat as “gospel” when managing anticoagulated patients during invasive procedures, as they help to safely prevent both thrombosis and bleeding during the procedure.

If the patient has had no thrombotic (clotting) episodes, the physician will likely wish to employ a careful history and physical before exposing the patient to the risk of antithrombotic therapy. A report of either protein C or protein S deficiency in the absence of clotting may not necessarily require therapy.

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