What to do with a patient on Eliquis (apixaban) with an elevated Prothrombin Time (PT)?

PT 17.3 in a Patient on Eliquis (Apixaban)

A PT of 17.3 seconds in a patient on apixaban (Eliquis) is expected and does not indicate clinically significant anticoagulation or require intervention in most cases, as PT and aPTT are insensitive to apixaban and cannot reliably exclude therapeutic or even supratherapeutic drug levels. 1

Understanding Apixaban's Effect on Coagulation Tests

Apixaban has minimal and unreliable effects on standard coagulation assays:

• Normal PT and aPTT do not exclude clinically relevant apixaban levels, and a prolonged PT only suggests the presence of on-therapy or above on-therapy levels but cannot quantify them 1
• The PT and aPTT are particularly insensitive to apixaban compared to other direct oral anticoagulants (DOACs) like rivaroxaban 1, 2, 3
• A PT of 17.3 seconds represents only mild prolongation and is commonly seen in patients on therapeutic apixaban without indicating excessive anticoagulation 4, 2

Clinical Assessment Algorithm

First, determine if the patient has active bleeding or requires urgent surgery:

If No Bleeding and No Urgent Procedure:

• No action is needed - continue apixaban as prescribed 5
• The PT elevation is an expected laboratory finding and does not guide clinical management 1
• Do not use PT/INR to monitor apixaban therapy or adjust dosing 6

If Active Major Bleeding is Present:

• Discontinue apixaban immediately and secure airway and large-bore IV access 1
• Consider reversal with andexanet alfa (specific reversal agent for factor Xa inhibitors) if available 5
• Prothrombin complex concentrate (PCC), activated PCC, or recombinant factor VIIa may be considered but have not been proven effective in clinical studies 5, 7
• Do not use PT, INR, or aPTT to monitor reversal effectiveness - these tests are not useful for this purpose 1

If Urgent Surgery or Invasive Procedure is Needed:

• Discontinue apixaban at least 48 hours prior to procedures with moderate or high bleeding risk 5
• Discontinue at least 24 hours prior to procedures with low bleeding risk 5
• Bridging anticoagulation is not generally required during this 24-48 hour period 5

Appropriate Laboratory Testing for Apixaban

If quantitative assessment of apixaban levels is truly needed (rare):

• Anti-factor Xa assay calibrated specifically for apixaban is the preferred test for quantitation 1
• If anti-Xa assay calibrated with UFH or LMWH standard is used, a level below the lower limit of quantitation probably excludes clinically relevant levels, but cannot quantify the drug 1
• Specialized assays like liquid chromatography-tandem mass spectrometry are reference standards but rarely available emergently 1

Common Pitfalls to Avoid

Critical mistakes in managing patients on apixaban with elevated PT:

• Do not assume a "normal" or mildly elevated PT means the patient is not anticoagulated - therapeutic apixaban levels can exist with normal coagulation tests 1, 3
• Do not use PT/INR values to adjust apixaban dosing as you would with warfarin - apixaban is dosed based on clinical factors (age ≥80, weight ≤60kg, creatinine ≥1.5), not laboratory values 6, 5
• Do not order routine PT/aPTT monitoring in stable patients on apixaban - these tests provide no useful information for dose adjustment 6
• Do not confuse apixaban's effect on INR with warfarin effect - apixaban affects INR measurements, making them unreliable during transition between these drugs 5

When to Investigate Further

Consider alternative causes of PT elevation if:

• The patient is not actually taking apixaban (verify medication history) 6
• PT is markedly elevated (>20 seconds) with clinical bleeding, suggesting possible concomitant coagulopathy 6
• Patient has liver disease, vitamin K deficiency, or other conditions that independently prolong PT 6
• Obtain CBC, fibrinogen, D-dimer, liver function tests, and aPTT if unexplained coagulopathy is suspected 6