To help evaluate a thrombotic episode and determine Protein C or Protein S deficiency
Proteins C and S help adjust the rate of blood clot formation. Thrombin is a clotting factor that can accelerate or decelerate blood clot formation. It forms a feedback loop that uses Protein C and Protein S to slow down the coagulation cascade. If there is not enough Protein C or Protein S, or if either one is not functioning normally, then thrombin generation goes on largely unchecked.
This can lead to excessive or inappropriate clotting that may block the flow of blood in the veins (VTE - venous thromboembolism) and, more rarely, in the arteries
Problems with Protein C and Protein S can be inherited or acquired.