What blood tests are required for patients taking Eliquis (apixaban) and what is its indication?

Blood Tests for Patients on Eliquis (Apixaban) and Its Indications

No routine blood tests are specifically required for monitoring patients taking Eliquis (apixaban), unlike warfarin which requires regular INR monitoring. 1

What is Eliquis (Apixaban)?

Eliquis (apixaban) is a direct factor Xa inhibitor that is FDA-approved for:

• Reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation
• Prophylaxis of deep vein thrombosis (DVT) following hip or knee replacement surgery
• Treatment of DVT and pulmonary embolism (PE)
• Reducing the risk of recurrent DVT and PE following initial therapy 2

Laboratory Assessment for Patients on Apixaban

Routine Monitoring

• No routine coagulation monitoring is required for patients taking apixaban 3
• Unlike warfarin, which requires regular INR monitoring, apixaban has a predictable effect without need for regular anticoagulation monitoring 1

Recommended Baseline and Follow-up Tests

While specific monitoring of drug levels isn't routinely required, the following tests are recommended:

• Renal function tests: Should be evaluated before starting treatment, when clinically indicated, and at least annually 3
• Complete blood count: To establish baseline hemoglobin/hematocrit and monitor for bleeding
• Liver function tests: To ensure appropriate hepatic function for drug metabolism

Special Situations Requiring Testing

In Case of Bleeding or Emergency Surgery

If a patient on apixaban presents with bleeding or requires emergency surgery, specific tests may be needed:

• Anti-Factor Xa assay: The preferred test for quantitation of apixaban when calibrated with apixaban 1
• Chromogenic anti-FXa assay: Shows linear dose-response curves with apixaban and can reliably measure apixaban concentration 4

When Anti-FXa Assays Are Not Available

• Standard PT and aPTT are not reliable for excluding clinically relevant apixaban levels 1
• A normal PT and aPTT do not exclude clinically relevant levels of apixaban 1
• UFH or LMWH anti-FXa below the lower limit of quantitation probably excludes clinically relevant apixaban levels 1

Dosing Considerations

Standard Dosing

• Standard dose: 5 mg twice daily for most patients with nonvalvular atrial fibrillation 3

Dose Reduction Criteria

Reduce 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 3

Renal Function Considerations

• No dose adjustment required for mild to moderate renal insufficiency (CrCl 30-50 mL/min) unless meeting other criteria 3
• Use with caution in severe renal insufficiency (CrCl 15-29 mL/min) 3

Important Clinical Pearls

• Common pitfall: Relying on PT or aPTT to assess apixaban activity. These tests are insensitive to apixaban and a normal result does not exclude therapeutic or even above-therapeutic levels 1

• Drug interactions: When using potent inhibitors of CYP3A4 and P-gp (such as ketoconazole, itraconazole, ritonavir), the dose of apixaban should be reduced 3

• Reversal in emergencies: For life-threatening bleeding in patients on apixaban, andexanet alfa is recommended. If unavailable, prothrombin complex concentrate (PCC) at 25-50 U/kg can be considered 1

• Monitoring signs: While routine lab monitoring isn't required, patients should be regularly evaluated for signs of bleeding 3

• Perioperative management: Apixaban should be discontinued before planned surgical procedures with moderate to high bleeding risk, typically 24-48 hours before the procedure depending on renal function and bleeding risk 1