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Tests for Erection Problems

Tests for erection problems can help find a cause for a man's problem in having or maintaining an erection (erectile dysfunction, or impotence). Erectile dysfunction is a common male problem. Most erection problems are caused by a combination of blood vessel, nerve, or psychological issues.

To find the cause of erection problems, your doctor will first ask about your sexual history and do a physical exam. During the physical exam, the doctor will:

Other tests that may be done as part of a physical exam include:

If the results of your physical exam and other tests are normal, your doctor may have you try a medicine, such as sildenafil (for example, Viagra), tadalafil (for example, Cialis), or vardenafil (for example, Levitra), before doing more tests.

This topic focuses on three more tests you may have after the physical exam and lab tests listed above. These three specific tests used to find the cause of erection problems are:

  • Nocturnal penile tumescence (NPT) test.
  • Intracavernosal injection test.
  • Doppler ultrasound.

Nocturnal penile tumescence (NPT) test

The NPT test checks whether a man is having normal erections during sleep. Most men have 3 to 5 full erections during deep (rapid eye movement, or REM) sleep. Men who do not have erections because of psychological problems can still have erections during deep sleep. Occasionally, some sleep problems or serious depression can prevent these normal nighttime (nocturnal) erections.

This test can be done at home or in a special sleep lab. One of two ways may be used.

  • A simple ringlike device called a snap gauge made up of plastic films is fitted around the penis. The films break at certain pressures. So an erection during sleep will cause the film to snap.
  • An electronic monitoring device records how many, how long, and how rigid the erections are during sleep. An electronic monitoring device is more expensive than using the snap gauge, but it is more accurate and gives more detailed information about erections during sleep.
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WebMD Medical Reference from Healthwise

Last Updated: May 14, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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