Doctor: Mr. Smith, your urine test is positive for cocaine.
Mr. Smith: [Blank Stare]
Doctor: Have you been snorting cocaine recently?
Mr. Smith: No.
Doctor: Then why is there cocaine in your urine?
Mr. Smith: Maybe your nurse put it in there.
Doctor: If my nurse had cocaine, I don’t think she’d put it in your urine.
Bonus tip for pain management specialists: cocaine’s half-life in the urine is 2-4 days. “Random” urine drug testing on Mondays offers a higher yield than other days of the business week because most patients abuse illicit drugs on weekends>>weekdays.