Knowing the differences between the tests is your key to proper code choice. • In a simple CMG (51725, Simple cystometrogram [e.g., spinal manometer]), the urologist places a small catheter in the bladder, fills the bladder by gravity, and measures capacity and storage pressures using a spinal manometer. • A complex CMG (51726, Complex cystometrogram [e.g., calibrated electronic equipment]) involves filling the bladder through a catheter and measuring the pressures with calibrated electronic equipment. If your urologist also performs a urethral pressure profile (UPP), report 51727 (Complex cystometrogram [i.e., calibrated electronic equipment]; with urethral pressure profile studies [i.e., urethral closure pressure profile], any technique). For a complex CMG with voiding pressure study, report 51728 (... with voiding pressure studies [i.e., bladder voiding pressure], any technique). For a complex CMG with voiding pressure study and UPP, use 51729 (... with voiding pressure studies [i.e., bladder voiding pressure] and urethral pressure profile studies [ie, urethral closure pressure profile], any technique). • During a simple UFR (51736, Simple uroflowmetry [e.g., stopwatch flow rate, mechanical uroflowmeter]), the urologist visually observes the urine flow, sometimes using a stopwatch to gauge and measure the flow. • A complex UFR (51741, Complex uroflowmetry [e.g., calibrated electronic equipment]) makes use of special electronic equipment to measure the urine flow. • EMG studies (51784, Electromyography studies of anal or urethral sphincter, other than needle, any technique), in which the urologist places skin patch electrodes on the perineum to measure electrical and muscular activity of the perineal muscles and urinary sphincter. • A needle EMG (51785, Needle electromyography studies of anal or urethral sphincter, any technique) involves placing needles into the pelvic floor to measure muscle activity during bladder filling and at rest. Few urologists use needle electromyography these days. • Stimulus evoked response (51792, Stimulus evoked response [e.g., measurement of bulbocavernosus reflex latency time]) involves stimulating the sacral arch via the glans or clitoris and measuring motor activity in the pelvic floor or urethral sphincter. Urologists rarely perform this test. • VP studies (+51797, Voiding pressure studies, intra-abdominal [i.e., rectal, gastric, intraperitoneal] [List separately in addition to code for primary procedure]) measure specific pressures during oiding. This is an add-on code that cannot be independently billed. You can bill is with 51728 or 51729. • Valsalva (abdominal) leak point pressure: The urologist asks the patient to bear down forcefully (Valsalva maneuver) while he observes the abdominal pressure at which leakage occurs from the bladder at the urethral meatus (around the urethral catheter) when the bladder has been filled with a minimum of 150 cc of fluid. The bladder pressure at leakage is called the leak point pressure. This is now included in 51727 and 51729.