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Tests for Erection Problems

How To Prepare

Nocturnal penile tumescence (NPT) test

Do not take any medicines that cause an erection, such as sildenafil (for example, Viagra), tadalafil (for example, Cialis), and vardenafil (for example, Levitra), before the test.

Do not drink alcohol or take sleeping pills for 2 days before you have a nocturnal penile tumescence (NPT) test. The alcohol and the pills can change your deep (REM) sleep time, which can affect nocturnal erections.

Intracavernosal injection test

If you are having an intracavernosal injection test, tell your doctor if you:

  • Are allergic to any medicine.
  • Have any bleeding problems or are taking blood-thinning medicine, such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin (Coumadin), clopidogrel (Plavix), or ticlopidine (Ticlid).
  • Have ever had an erection lasting more than 3 hours (priapism).

Doppler ultrasound

You may be asked to avoid products that contain nicotine (cigarettes, chewing tobacco) for 30 minutes to 2 hours before the test.

How It Is Done

Nocturnal penile tumescence (NPT) test

It is helpful if you wear briefs-type underwear (not boxer shorts) with a fly front when you are ready for bed. Put your penis through the fly front and keep your pubic hair inside the underwear out of the way. Put the device around your penis. After you put the device on, carefully put your penis inside your underwear.

The types of devices you can use include:

  • Snap gauge. A snap gauge is a ringlike device made up of plastic films that fit around the penis. The films break at certain pressures. A snap gauge will break during an erection. It can also tell how firm the penis became during the erection. This test is usually done 2 or 3 nights in a row.
  • Electronic devices. Electronic devices measure changes in the fullness of the penis. The devices have one or more elastic loops that fit around the penis. These are hooked to a small unit that records changes as the loops are stretched.

Intracavernosal injection test

The intracavernosal injection test is generally done by a urologist in the office or clinic. For this test, you will need to take off all of your clothes below the waist, and you will be given a cloth or paper gown to use.

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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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