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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
PubMed
Abstract

Insights

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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