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Case report: artificial elevation of prothrombin time by telavancin
Derek F Amanatullah1, Matthew J Lopez, Robert C Gosselin
1Department of Orthopaedic Surgery, University of California, Davis Health System, 4860 Y Street, Suite 3800, Sacramento, CA 95835, USA.
Clinical Orthopaedics and Related Research
|November 7, 2012
Summary
Telavancin can falsely elevate prothrombin time (PT/INR) test results, impacting surgical decisions. Use alternative reagents or time tests to obtain accurate international normalized ratio (INR) readings.
Area of Science:
- Pharmacology
- Clinical Chemistry
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) infections pose surgical risks.
- Telavancin is an antibiotic used for S. aureus infections.
Observation:
- A patient on telavancin showed an elevated PT/INR (2.05) pre-surgery.
- Telavancin was identified as a potential cause for the abnormal PT/INR.
- In vitro testing confirmed telavancin's dose-dependent interference with PT/INR assays.
Findings:
- Telavancin interferes with phospholipid-based PT/INR testing reagents.
- This interference leads to falsely elevated international normalized ratio (INR) values.
- An alternative PT/INR reagent yielded a true INR of 0.97, unaffected by telavancin.
Implications:
- Physicians, particularly orthopaedic surgeons, must recognize telavancin's effect on PT/INR.
- Accurate INR monitoring is crucial for surgical safety.
- Employing telavancin-unaffected reagents or strategic test timing ensures reliable coagulation assessment.
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