Bleeding Time

• Test: A Small Incision is Made in a Standardized Fashion and Time is Recorded Until Bleeding Stops
• Evaluates: Platelet Function (Adhesion and Aggregation)
  • Not Effected by Coagulation Factor Disorders
• Normal Time: 1-9 Minutes

Prothrombin Time (PT)

• Test: Thromboplastin is Added to Plasma and Time is Recorded Until Clot Forms
• Evaluates: Extrinsic and Common Coagulation Pathway Function
  • Factors II, V, VII, and X
• The Best Test for Synthetic Liver Function
• Normal Time: 10-12 Seconds

Partial Thromboplastin Time (PTT)

• Test: Calcium and Activated Substances (Kaolin and Cephalin) are Added to Plasma and Time is Recorded Until Clot Forms
• Evaluates: Intrinsic and Common Coagulation Pathway Function
  • All Factors Except VII and XIII
• Goal for Anticoagulation: 60-100 Seconds
• Normal Time: 30-45 Seconds

International Normalized Ratio (INR)

• A Calculated Value from Prothrombin Time (PT)
• Evaluates: Extrinsic and Common Coagulation Pathway Function
• Normal INR: 1.0
• Goal for Anticoagulation: 2.0-3.0
  • May Be Higher for Prosthetic Heart Valves

Activated Clotting Time (ACT)

• Bedside Test Measuring Time to Clot Formation After Activation by Kaolin or Celite
• Used to Monitor Intraoperative Coagulation Function During Cases Using High Doses of Heparin
  • May Be Obtained Every 20-30 Minutes During the Case
• Normal Time: 70-120 Seconds
• Therapeutic Goals:
  • Dialysis: 160-180 Seconds
  • Vascular Surgery: > 150-200 Seconds
  • CABG: 480-600 Seconds
• Same as R Time in TEG