Laboratory Monitoring for Apixaban at 1-Week Follow-Up
No routine laboratory monitoring is required for patients on apixaban (Eliquis) for DVT treatment. Direct oral anticoagulants like apixaban do not require the coagulation monitoring (INR, aPTT) that warfarin or heparin necessitate 1.
Recommended Laboratory Testing
While routine anticoagulation monitoring is unnecessary, the following baseline and surveillance labs should be obtained:
Essential Labs at This Visit:
- Complete blood count (CBC) - Check hemoglobin, hematocrit, and platelet count to assess for bleeding complications 1
- Renal function panel - Creatinine clearance (CrCl) assessment is critical, as apixaban is approximately 27% renally eliminated and should be avoided if CrCl <15 mL/min 1
- Hepatic function panel - Liver enzymes and bilirubin, as apixaban is primarily metabolized via cytochrome P450 3A4 in the liver 1
Monitoring Schedule:
According to NCCN guidelines, after initiating anticoagulation, hemoglobin, hematocrit, and platelet counts should be checked at least every 2-3 days for the first 14 days, then every 2 weeks thereafter or as clinically indicated 1. Since your patient is at 1 week, she falls within this initial monitoring window.
Clinical Assessment Priorities
Beyond laboratory testing, focus on:
- Bleeding assessment - Ask specifically about any signs of major bleeding (gastrointestinal, intracranial, genitourinary) or clinically relevant non-major bleeding 1
- Symptom improvement - Evaluate for resolution of DVT symptoms (leg pain, swelling, erythema)
- Medication adherence - Confirm the patient is taking apixaban 5 mg twice daily as prescribed
- Drug interactions - Review for new medications, particularly CYP3A4 inhibitors/inducers that could affect apixaban levels 1
Important Caveats
Apixaban does not require INR or aPTT monitoring unlike warfarin or heparin 1. Anti-Xa levels can be measured in special circumstances (severe renal impairment, suspected bioaccumulation, extremes of body weight), but this is not standard practice 2, 3.
The patient should continue apixaban 5 mg twice daily for at least 3 months total, after which extended therapy decisions should be made based on whether the DVT was provoked or unprovoked 1.