The protein C test in citrated plasma is a laboratory test used to assess the function of protein C, a protein that plays an important role in regulating blood clotting. This test helps determine the body’s ability to prevent excessive clotting, reducing the risk of thrombus formation. Protein C works by activating other proteins that contribute to breaking down blood clots. A deficiency or dysfunction of protein C is a risk factor for conditions such as deep vein thrombosis or pulmonary embolism. The test is performed by drawing a blood sample treated with citrate, which prevents clotting. The results are used to diagnose clotting disorders and guide appropriate treatment options, helping to improve patient care and reduce potential risks.