Protein S is a crucial protein that helps keep blood from clotting excessively. In order to stop the body from losing too much blood, blood clots grow after an injury. An genetic condition known as protein S deficiency raises the chance of blood clots developing and spreading to the arms, legs, and even the lungs, where they can cause pulmonary embolism. The purpose of this test is to identify coagulation problems. If youve had several miscarriages, a family history of blood clots, or unexplained blood clots since clotting can occasionally influence pregnancy, you might need this test.