Tests and diagnosis - erectile dysfunction

Your doctor will ask questions about how and when your symptoms developed, what medications you take and any other physical conditions you might have. Your doctor will also want to discuss recent physical or emotional changes.
If your doctor suspects that physical causes are involved, he or she will likely want to take blood tests to check your level of male hormones and for other potential medical problems, such as diabetes. Your doctor may also want to try eliminating or replacing certain prescription drugs you're taking one at a time to see whether any are responsible for erectile dysfunction.
More specialized tests may include:
Ultrasound. This test can check blood flow to your penis. It involves using a wand-like device (transducer) held over the blood vessels that supply the penis. The transducer emits sound waves that pass through body tissues and reflect back, producing an image to let your doctor see if your blood flow is impaired. The test often is done before and after injection of medication into the side of the penis to see if there's an improvement in blood flow.
Neurological evaluation. Your doctor usually assesses possible nerve damage by conducting a physical examination to test for normal touch sensation in your genital area.
Dynamic infusion cavernosometry and cavernosography (DICC). This procedure involves injecting a dye into penile blood vessels to permit your doctor to view any possible abnormalities in blood pressure and flow into and out of your penis. It's generally done with local anesthesia by a urologist who specializes in erectile dysfunction.
Nocturnal tumescence test. If your doctor suspects that mainly nonphysical causes are to blame, he or she may ask whether you obtain erections during masturbation, with a partner or while you sleep. Most men experience many erections, without remembering them, during sleep. A simple test that involves wrapping a special perforated tape around your penis before going to sleep can confirm whether you have erections while you're sleeping. If the tape is separated in the morning, your penis was erect at some time during the night. Tests of this type confirm that there is not a physical abnormality causing erectile dysfunction, and that the cause is likely psychological.