Question 1

When should trough levels be drawn?

Accepted Answer

Draw the trough level within 30–60 minutes before the fourth dose (at steady state for patients with normal renal function). Dose adjustments should be followed by a repeat trough after 2–3 doses on the new regimen.

Question 2

Is the trough target the same for continuous infusion vancomycin?

Accepted Answer

No — for continuous infusion, the target steady-state concentration (Css) is 20–25 μg/mL (15–25 μg/mL in some protocols). The tool is designed for intermittent infusion (every 6–24 hours) only.

Question 3

Can I still use trough monitoring if my institution has transitioned to AUC?

Accepted Answer

Yes — trough monitoring can complement AUC monitoring. A stable trough of 10–15 μg/mL in a patient with stable renal function correlates approximately with an AUC24 of 400–600 mg·h/L. However, the trough-to-AUC relationship varies significantly between patients; AUC calculation remains the preferred parameter for initial dosing and in unstable renal function.