The Primary Care Provider Orders Peak and Trough Levels for a Patient

The primary care provider orders peak and trough levels for a patient who is receiving intravenous vancomycin every 12 hours.When should the nurse obtain a blood specimen to measure the trough?

A) With the morning routine laboratory studies
B) Approximately 30 minutes before the next dose
C) Two hours after the next dose infuses
D) While the drug infuses