If my doctor does an ED test, what does that mean?

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
The most common erectile dysfunction (ED) test, the nocturnal penile tumescence (NPT) test, helps your doctor determine whether a physical cause is the primary reason why you have ED. This test helps determine whether you have erections during the night. If you do, it's a sign that your ED is not caused primarily by a cardiovascular problem, and you may have other causes, including psychological issues. 
To check whether you have any health conditions that can cause erectile dysfunction (ED), your doctor performs a thorough physical workup that includes a blood pressure measurement; examination of your penis and testicles; and blood and urine tests to check for anemia (low red blood cell count), high blood cholesterol, diabetes, low testosterone, and a liver or kidney problem. The doctor may also test your bulbocavernosus reflex, which is a fancy way of saying that the head of your penis will be squeezed to test nerve function.

If the physical exam and lab tests show that you have a health condition that decreases blood flow to the penis or interferes with nerve signals that enable arousal and erection, the doctor may order a penile ultrasound scan to image blood vessels and tissues in the penis. The test can show whether blood vessels have become leaky or are narrowed because of cardiovascular (heart and vessel) disease, as well as whether there is hardened scar tissue in the penis (a condition known as “Peyronie’s disease”) that can interfere with an erection.

The doctor may also want to determine whether you have erections in your sleep with the Nocturnal penile tumescence (NPT) test. Men typically have three to five erections while sleeping, and if you aren’t, it may be due to a health condition or medication that decreases blood flow to the penis or interferes with nerve signals that enable arousal and erection. If you experience erections in your sleep or upon awakening, your erectile dysfunction (ED) may be caused by stress or depression.

Whatever the cause of your difficulty in getting or maintaining an erection, your doctor can recommend treatment that will help. 

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.