A medical device includes an elongate body configured to be disposed within a urinary tract of a patient such that a first end portion of the elongate body is disposed at a first location of the urinary tract and a second end portion of the elongate body is disposed at a second, different location of the urinary tract. The elongate body defines a lumen that is configured to convey urine from the first location of the urinary tract to the second location of the urinary tract. An agent is formulated to visually alter urine of the patient, the agent is coupled to the elongate body and releasable into the patient's urine.