Are These PT/INR Results Normal?
No, these results are not normal—the PT is elevated at 16.6 seconds (reference 9.6-12.6) and the INR is elevated at 1.51 (reference 0.87-1.13), but these values are clinically insignificant and require no intervention in this patient taking only aspirin for MI prevention with a recent femur fracture. 1, 2
Understanding the Results in Clinical Context
Why These Values Are Elevated But Not Concerning
- PT/INR is designed specifically to monitor vitamin K antagonist (warfarin) therapy, not to predict bleeding risk in patients not taking warfarin 1, 2
- Your patient is taking only baby aspirin (acetylsalicylic acid), which does not affect PT/INR values 1
- INR values between 1.0-2.0 in patients not on anticoagulation have no proven clinical significance and do not predict bleeding risk 2, 3
- A systematic review found weak or no association between pre-procedural INR and bleeding in 78 out of 79 studies, with sensitivity under 50% 2
What Could Cause This Mild Elevation
The mild PT/INR elevation (1.51) in a non-anticoagulated patient may reflect:
- Laboratory variability including thromboplastin reagent differences, collection tube issues, or automated detection methods 1
- Early liver dysfunction affecting synthesis of clotting factors, though this would typically require more significant elevation 1, 3
- Consumption of coagulation factors from the acute trauma (femur fracture), though again this is a very mild elevation 1
Management Recommendations
No Treatment Required
- For asymptomatic patients with INR 1.0-2.0 not on anticoagulation, observation only is recommended—plasma transfusion provides no clinical benefit 3
- Do not transfuse plasma to "correct" this INR value, as randomized trials found no reduction in bleeding when prophylactic plasma was given for mildly elevated INR 2
Perioperative Considerations for Femur Fracture Surgery
- Aspirin monotherapy does not require discontinuation prior to orthopedic surgery for femur fracture 4
- Surgery should proceed within 24 hours as planned to reduce mortality and morbidity 4
- Neuraxial anesthesia is safe when the patient is taking aspirin 4
- Aspirin is effective VTE prophylaxis for ambulatory patients with femoral neck fracture undergoing hip arthroplasty 5
What to Monitor Instead
- Clinical bleeding signs rather than laboratory values 2, 3
- Platelet count, fibrinogen level, and aPTT as part of comprehensive coagulation assessment if bleeding occurs 2
- Consider viscoelastic testing (TEG/ROTEM) if available for more accurate coagulation assessment in trauma patients, as standard PT/INR represents only the first 4% of thrombin production 2
Common Pitfalls to Avoid
- Do not use PT/INR as a general screening test for coagulopathy in non-warfarin patients—it lacks validity for this purpose and leads to unnecessary interventions 1, 2
- Do not delay necessary surgery to "normalize" this INR value—early surgery within 24 hours improves outcomes in femur fracture patients 4
- Do not assume this INR predicts bleeding risk—the INR scale is only validated for patients on vitamin K antagonists with no other superimposed coagulation defects 1
- Do not discontinue aspirin perioperatively—current evidence supports continuing aspirin through orthopedic trauma surgery 4, 5
Post-Operative Anticoagulation
- Resume or continue aspirin 75-162 mg daily indefinitely for MI prevention 6
- Consider aspirin as VTE prophylaxis post-operatively rather than more potent anticoagulation in standard-risk ambulatory patients 5
- If warfarin becomes indicated post-operatively (e.g., atrial fibrillation develops), target INR 2.0-3.0 6, 3