From Activated Partial Thromboplastin Time to Antifactor Xa and Back Again

Area of Science:

• Clinical Pathology
• Pharmacology
• Laboratory Medicine

Background:

• Effective anticoagulation monitoring is crucial for patient safety.
• Laboratory testing strategies for anticoagulation require continuous adaptation.
• Collaboration between pathologists, clinicians, and pharmacists is essential.

Purpose of the Study:

• To describe the evolution of laboratory testing strategies for unfractionated heparin (UFH) monitoring.
• To address challenges in anticoagulation management due to new oral anticoagulants.
• To highlight the role of clinical pathologists in adapting laboratory protocols.

Main Methods:

• Retrospective review of laboratory testing protocols for unfractionated heparin (UFH).
• Comparison of activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) assay results.
• Adaptation of laboratory protocols to accommodate patients on oral factor Xa inhibitors.

Main Results:

• Initial transition from aPTT to anti-Xa assays due to discordance in UFH monitoring.
• Identification of interference of oral factor Xa inhibitors with anti-Xa assays.
• Re-incorporation of aPTT testing for patients transitioning to UFH from oral factor Xa inhibitors.

Conclusions:

• Clinical pathologists play a vital role in navigating the complexities of anticoagulation monitoring.
• Adapting laboratory testing is critical for safe and effective anticoagulation prescribing.
• Healthcare systems must remain agile to address the evolving landscape of anticoagulant therapies.