Protein S Antigen Test

The Protein S Antigen Test is a blood test that measures the levels of Protein S in the blood. Protein S is a protein that helps prevent blood clots from forming by inhibiting the coagulation process.

The test is often ordered to evaluate the risk of blood clots, especially in people with a history of abnormal clotting, such as deep vein thrombosis (DVT), pulmonary embolism (PE), or recurrent miscarriages. It can also be used to monitor the effectiveness of anticoagulant therapy in patients who are taking blood thinners.

The Protein S Antigen Test is usually performed along with other blood tests such as the Protein S Activity Test, which measures the functional activity of Protein S. This is because Protein S can exist in two forms in the blood, one of which is active and the other is inactive. Measuring both forms can give a more accurate assessment of the patient's risk of clotting.

It is important to note that abnormal results on the Protein S Antigen Test do not necessarily mean that a person will develop blood clots. Other factors such as age, lifestyle, and medical history can also contribute to the risk of clotting. Therefore, the test should be interpreted by a healthcare professional in the context of the patient's overall health and medical history.