Ideally a serum drug level would be monitored frequently and consistently, providing the clinician with a detailed pharmacokinetic profile over time.
In reality, serum samples are often measured only during relatively infrequent clinic visits, meaning that many days or weeks may pass before a drug concentration 'snap-shot' is taken. This then requires us to ask, "When should we collect blood in order to best measure the serum concentration of the drug in question?"
