A client is receiving IV vancomycin for treatment of infection, and the peak drug level needs to be drawn to evaluate therapy. Which statement correctly describes how a peak drug level should be drawn?

A. Check 15-30 minutes after the dose has been given: The peak level represents the highest concentration of the drug in the bloodstream and is measured shortly after the infusion is complete, typically 15–30 minutes post-dose. This timing allows for distribution of vancomycin into tissues while reflecting the maximum plasma concentration. B. Check 15-30 minutes before the next dose is due: A sample drawn immediately before the next dose reflects the trough level, not the peak. Trough levels are used to assess minimum drug concentrations and ensure that therapeutic levels are maintained without accumulation. Drawing at this time does not provide information about the peak plasma concentration. C. Check exactly halfway between the last dose and the next dose: Measuring mid-interval drug concentration does not accurately represent either the peak or the trough. Levels taken at this time may underestimate peak concentrations and overestimate troughs, making interpretation unreliable for dosing adjustments. D. Check while the drug is being administered: Drawing a blood sample during the infusion can result in falsely elevated levels due to the immediate presence of the drug in the IV line. This does not provide a true peak after distribution into tissues and can lead to misinterpretation of therapeutic levels.