What labs are required for patients on Eliquis (apixaban)?

Laboratory Monitoring Requirements for Patients on Apixaban (Eliquis)

Patients on apixaban do not require routine laboratory monitoring of anticoagulation effect, but should have regular assessment of renal function at least yearly, with more frequent monitoring in high-risk patients. 1, 2

Essential Laboratory Tests for Apixaban Patients

Initial Baseline Tests

• Complete blood count (CBC)
• Renal function tests:
  • Serum creatinine
  • Creatinine clearance (CrCl)
• Liver function tests (LFTs)

Monitoring Schedule

• Renal function: At least yearly for stable patients 1
• More frequent renal monitoring (every 3-6 months) for:
  • Elderly patients (≥80 years)
  • Patients with baseline impaired renal function
  • Patients with CrCl 15-30 mL/min (use with caution) 2
  • Patients on concomitant medications affecting renal function

Immediate Assessment Required

• Immediate renal function assessment during:
  • Acute illness
  • Dehydration
  • Congestive heart failure exacerbation
  • Infections
  • Acute inflammatory disorders
  • Hospitalization 1

Special Considerations for Dose Adjustment

Dose Reduction Criteria

Apixaban dose should be reduced to 2.5 mg twice daily if patient has at least two of:

• Age ≥80 years
• Body weight ≤60 kg
• Serum creatinine ≥1.5 mg/dL 2

Renal Function Thresholds

• CrCl <15 mL/min: Apixaban generally not recommended
• CrCl 15-30 mL/min: Use with caution, monitor renal function more frequently 2
• Severe renal impairment: Associated with higher bleeding risk when using standard 5 mg dosing 3

Perioperative Management and Laboratory Assessment

For patients requiring surgery:

• Low bleeding risk procedures: Interrupt apixaban 24 hours before procedure
• High bleeding risk procedures: Interrupt apixaban 3 days before procedure 2
• Patients with impaired renal function: May require longer interruption periods 1

In urgent surgical situations:

• Consider measuring apixaban levels with anti-factor Xa assays calibrated for apixaban 1
• Note that routine coagulation tests (INR, aPTT) are insensitive for residual apixaban effect 1

Important Monitoring Considerations

Standard Coagulation Tests

• PT, aPTT, and INR are not reliable for monitoring apixaban effect 4
• These tests show concentration-dependent prolongation but lack sensitivity 4

Specialized Testing (if needed)

• Anti-factor Xa assays calibrated specifically for apixaban are the preferred test if drug level assessment is required 1, 4
• These tests should only be used in special circumstances (urgent surgery, suspected overdose, bleeding)

Drug Interactions Requiring Monitoring

• Monitor more closely when adding medications that:
  • Inhibit CYP3A4 and P-glycoprotein pathways
  • Affect renal function
  • Increase bleeding risk (NSAIDs, antiplatelet agents) 2

Conclusion

Unlike warfarin, apixaban does not require routine coagulation monitoring. The primary laboratory requirement is regular assessment of renal function, with the frequency determined by patient risk factors. Anti-factor Xa assays calibrated for apixaban should be reserved for special circumstances where drug level assessment is clinically necessary.