Description

This profile measures the activity of three natural anticoagulant proteins in the body: Protein C, Protein S, and Antithrombin III. These proteins help regulate normal blood clotting and prevent excessive clot formation.

Reduced activity of any of these factors may increase the risk of abnormal or recurrent blood clots.

This panel is commonly used to evaluate inherited or acquired clotting disorders.

What does this profile measure?

Protein C Activity Protein C helps slow clot formation and prevent excessive clotting. Low activity may increase the risk of venous thrombosis.

Protein S Activity Protein S works together with Protein C to regulate clotting. Reduced activity can contribute to inherited thrombophilia or acquired clotting disorders.

Antithrombin III Activity Antithrombin III helps inhibit clotting enzymes. Low levels may significantly increase the risk of blood clots and can affect response to certain anticoagulant medications.

Why is this test important?

Reduced activity of these natural anticoagulants may be associated with:

  • Recurrent blood clots
  • Deep vein thrombosis (DVT)
  • Pulmonary embolism
  • Early or unexplained stroke
  • Inherited thrombophilia
  • Clotting at a young age
  • Clotting despite normal routine labs

This testing helps identify underlying clotting tendencies that are not detected with standard coagulation panels.

Who should consider this test?

This profile may be helpful for individuals who have:

  • Personal or family history of blood clots
  • Clotting at a young age
  • Recurrent DVT or pulmonary embolism
  • Unexplained stroke or TIA
  • Clotting while on hormone therapy
  • Strong family history of thrombophilia
  • Evaluation prior to long-term anticoagulation decisions

How is this test used?

This profile is commonly used in:

  • Thrombophilia evaluations
  • Recurrent clotting investigations
  • Advanced cardiovascular risk screening
  • Family history clotting workups
  • Pre-surgical or pre-hormone therapy risk assessments

It is often ordered alongside other clotting markers such as antiphospholipid antibodies or genetic thrombophilia testing.

Do I need to fast for this test?

Fasting is not required for this profile.