Protein C and Protein S
Definition
Protein C and protein S are two proteins that work together to prevent excessive clotting. The test measures how much of these proteins is present and how well they work.
Purpose
Investigating the cause of unexplained blood clots; detecting deficiency; distinguishing whether a deficiency is due to a low amount or to impaired function; monitoring treatment effectiveness.
Results
Levels lower than normal, or proteins that are not working properly, indicate an increased risk of clot formation. High levels have no known harm.
Normal Values
Laboratory specific, refer to the reference range on your report.
Risks and Limitations
In this test, timing determines the result:
The test cannot be done immediately after a clotting event, if done too early the results will not be accurate. Your physician will tell you when to have the test. Use of blood thinners affects the result. For this reason the medication may need to be temporarily stopped, but no prescription medication should be stopped without consulting a physician.