Apixaban Does Not Interfere With Protein S or Activated Protein C Resistance (Factor V Leiden) Testing Using...

Area of Science:

• Hematology
• Pharmacology
• Clinical Diagnostics

Background:

• Apixaban, a direct oral anticoagulant, can potentially interfere with hypercoagulation testing.
• Activated protein C resistance (APCR) assays and protein S activity tests are crucial for diagnosing thrombophilia.
• Understanding apixaban's impact on these tests is vital for accurate patient management.

Purpose of the Study:

• To determine if apixaban use masks factor V Leiden (FVL) or protein S deficiency diagnoses.
• To evaluate apixaban's effect on APCR ratios and protein S activity in patients undergoing hypercoagulation testing.

Main Methods:

• A comparative study of 58 patients over 4.5 years, analyzing four groups: FVL heterozygous on apixaban, wild-type on apixaban, FVL heterozygous off apixaban, and normal APCR off apixaban.
• Protein S functional activity and free antigen levels were assessed in 40 patients on apixaban.
• APCR ratios were compared between groups, with a focus on FVL-HET patients on apixaban.

Main Results:

• FVL-HET patients on apixaban showed lower APCR ratios than wild-type patients (P < .001).
• No FVL diagnoses were missed in patients taking apixaban, as APCR results remained distinguishable.
• Apixaban did not significantly interfere with protein S activity or antigen assessment; 8% of patients had low protein S levels, correctly identified.

Conclusions:

• APCR testing effectively distinguishes FVL-HET from healthy individuals even with apixaban treatment.
• Indiscriminate FVL DNA testing for all patients on apixaban is unnecessary.
• Apixaban does not negatively impact the assessment of protein S activity, ensuring accurate deficiency diagnosis.