All these tests are sequential and after confirmation of a diagnosis the next test may be unnecessary. RGU and MCU refer to retrograde urethrogram and micturating cystogram, radiological tests to delineate urethral narrowings and bladder shape abnormalities by injecting a dye through urethra. If these are normal, the next logical test is Urodynamic evaluation to detect functional abnormalities. Cystoscopy, as the most invasive test, is usually reserved as the last investigation.