During a physical examination, the doctor looks at the meatus and other pelvic organs for any abnormalities. Basic evaluation includes blood and urine tests, an ultrasound scan (before and after passing urine), and uroflowmetry (in which the patient passes urine in a commode like a machine which records flow rates in a graphic manner).
If these tests are abnormal, further imaging tests called Micturating cystourethrogram (MCU) will be asked for. In MCU, the contrast material is injected with help of a needle puncture of the full bladder and X-ray images are taken while passing urine. This will help the doctor to study the urethra. Note: this investigation should not be done if you are pregnant. By this imaging, your doctor can differentiate from other conditions which present with similar symptoms.
Finally, if all the above tests are indicative of stricture, then we confirm it by urethral calibration, by checking if a certain size catheter enters the bladder easily. If it does, there is no stricture. If not, the position at which the tube gets held up is noted. This is done under local anesthesia