APTT Blood Test Lecture Notes

Introduction

• Speaker: Sarah from RegisteredNurseRN.com
• Topic: APTT blood test
• Purpose: To assess how fast blood clots and identify potential bleeding disorders.
• Additional Resources: Free quiz available on the website.

What is APTT?

• APTT: Activated Partial Thromboplastin Time
• Purpose: Measures clotting time to assess blood coagulation.
• Procedure:
  • Blood is drawn from a patient's vein.
  • Blood is placed in a special tube.
  • Sent to lab for testing.
• Use Cases:
  • To diagnose bleeding disorders.
  • To monitor patients on heparin.

Role of Heparin

• Heparin: Indirect thrombin inhibitor
• Function of Thrombin: Converts fibrinogen to fibrin, aiding in clot formation.
• Heparin Action:
  • Enhances antithrombin 3, preventing thrombin activation.
  • Prolongs clot formation by delaying the coagulation cascade.

Coagulation Cascade

• Purpose: To prevent blood loss from vascular injuries.
• Pathways:
  • Intrinsic Pathway: Activated by internal vascular system damage.
  • Extrinsic Pathway: Activated by external injury, leading to blood loss.
  • Common Pathway: Intersection of intrinsic and extrinsic pathways to form clots.
• Clotting Factors in Pathways:
  • Intrinsic Pathway: Factors 12, 11, 9, 8
  • Common Pathway: Factors 1, 2, 5, 10

APTT vs. PTT

• APTT:
  • Includes an activator agent to speed up clotting
  • Provides a narrow range of results
  • Normal range: 30-40 seconds
• PTT:
  • Measures the same pathways without an activator agent
  • Therapeutic range for patients on heparin: 60-70 seconds

Clinical Application

• Nursing Considerations:
  • Understanding normal ranges for APTT.
  • Adjusting therapeutic ranges for heparin therapy (1.5 to 2.5 times the normal range).

Conclusion

• APTT blood tests are crucial for diagnosing coagulation issues and managing heparin therapy.
• Reminder: Access available free quiz to test understanding of content.