What lab value indicates when to hold Eliquis (apixaban)?

Lab Values to Monitor for Holding Eliquis (Apixaban)

The most important lab value to monitor when considering whether to hold Eliquis is the calibrated anti-Xa assay, which directly measures apixaban drug levels, with thresholds of 30-50 ng/mL indicating when it's safe to proceed with procedures. 1

Monitoring Apixaban Levels

Apixaban levels can be monitored using several laboratory tests, but they vary in accuracy and clinical utility:

Preferred Test

• Calibrated chromogenic anti-Xa assay: This is the gold standard test for measuring apixaban levels 1, 2
  • Threshold levels:
    • <30 ng/mL: Generally safe for most procedures
    • <50 ng/mL: Reasonable threshold for most procedures

    • 50 ng/mL: Consider holding Eliquis or delaying procedure 1

Alternative Tests (Less Reliable)

• Heparin-calibrated anti-Xa assays: Shows approximately linear relationship for Factor Xa inhibitor levels between 30-100 ng/mL, but becomes nonlinear at concentrations <30 ng/mL or >150 ng/mL 1
• Prothrombin Time (PT) and INR: These are affected by apixaban but have poor sensitivity and significant variability between reagents, making them unreliable for monitoring apixaban levels 3

When to Hold Eliquis Based on Creatinine Clearance

When specific anti-Xa testing isn't available, the decision to hold Eliquis should be based on creatinine clearance (CrCl) and the procedure's bleeding risk:

For Transradial Procedures

• Hold for ≥24 hours if CrCl ≥30 mL/min
• Hold for ≥36 hours if CrCl 15-29 mL/min
• Hold for ≥48 hours if CrCl <15 mL/min 1

For Transfemoral Procedures (Higher Bleeding Risk)

• Hold for ≥48 hours if CrCl ≥30 mL/min
• Hold for ≥72 hours if CrCl <29 mL/min 1

For High Bleeding Risk Procedures

• Hold for 3 days before procedure when CrCl >30 mL/min 1

Monitoring Considerations

• Anti-Xa assays calibrated specifically for apixaban provide the most accurate measurement of drug levels 2
• The correlation between apixaban plasma concentration and anti-Xa activity (r²=0.88-0.89) is much stronger than with PT/INR (r²=0.36) 3
• Routine monitoring is not required for most patients on Eliquis, but may be necessary in specific situations such as emergency surgery, bleeding events, or suspected drug accumulation 1

Common Pitfalls

• Relying on PT/INR: While apixaban can elevate INR (84.5% of hospitalized patients show elevated INR on day 1 of therapy), INR is not a reliable indicator of apixaban activity 4
• Inadequate holding time: Not accounting for renal function when determining holding time
• Drug interactions: Concomitant use of P-glycoprotein inhibitors (like amiodarone or diltiazem) can increase apixaban levels and may require longer holding periods 5
• Assuming all anti-Xa assays are equivalent: Different anti-Xa assays have different dynamic ranges for each Factor Xa inhibitor 3

Remember that apixaban has a half-life of approximately 12 hours, and elimination occurs via multiple pathways with only about 27% of clearance occurring via renal excretion 6. This should be considered when determining appropriate holding times.