Overview

• Find out when the patient took the last dose of the drug in question, and determine the best time to take the blood level.
• Trough levels - take the blood just prior to the next dose (do not withhold the dose while you wait for the result unless you're concerned that it's too high)
• Peak levels - find out the optimal time to take the sample
• Area under the curve (e.g. gentamicin) - consult guidelines and take blood at two set points following drug administration