Coagulation Profile: Blood Clotting Test Guide

What is a Coagulation Profile?

A coagulation profile is a blood test that measures your body's ability to form clots and break them down. These tests assess bleeding and clotting disorders, monitor anticoagulant therapy, and evaluate bleeding risk before surgery. They're crucial for diagnosing hemophilia, thrombophilia, and other clotting disorders.

Key Coagulation Tests

1. Prothrombin Time (PT/INR)

Measures the time it takes blood to clot via the extrinsic pathway. INR (International Normalized Ratio) standardizes results across laboratories. Normal PT: 11-13.5 seconds, Normal INR: 0.8-1.1. It monitors warfarin therapy.

2. Activated Partial Thromboplastin Time (aPTT)

Measures the intrinsic and common coagulation pathways. Normal: 25-35 seconds. Used to monitor heparin therapy and screen for clotting factor deficiencies and inhibitors.

3. Platelet Count

Measures platelet number. Normal: 150,000-400,000/mcL. Low platelet counts (thrombocytopenia) increase bleeding risk, while high counts (thrombocytosis) increase clot formation risk.

4. Thrombin Time (TT)

Measures fibrinogen conversion to fibrin. Normal: 11-15 seconds. Prolonged TT suggests fibrinogen deficiency or dysfunction, or presence of anticoagulants.

5. Fibrinogen

Protein essential for clot formation. Normal: 200-400 mg/dL. Low fibrinogen increases bleeding risk, while high levels increase clot formation and thrombosis risk.

Bleeding Disorders

• ✓ Hemophilia A & B: Clotting factor deficiencies
• ✓ von Willebrand Disease: Most common inherited bleeding disorder
• ✓ Disseminated Intravascular Coagulation (DIC): Excessive clotting and bleeding
• ✓ Vitamin K Deficiency: Affects multiple clotting factors
• ✓ Thrombophilia: Increased clotting tendency

When Should Coagulation Tests Be Performed?

Before surgery or invasive procedures, when evaluating easy bruising or excessive bleeding, for bleeding disorder screening, to monitor anticoagulant medications, and when assessing thrombotic disorders.

Monitoring Anticoagulation

INR monitoring is essential for patients on warfarin to maintain therapeutic levels. PT/INR testing should be done regularly—typically weekly initially, then monthly once stable. Dosage adjustments are made based on results.

Symptoms Warranting Testing

• • Easy bruising or excessive bleeding
• • Heavy menstrual bleeding
• • Prolonged bleeding after injuries
• • Blood in urine or stool
• • Family history of bleeding disorders