Skip to content

Erectile Dysfunction Health Center

Font Size

Tests for Erection Problems

Tests are usually done for at least two nights in a row. If good erections occur during sleep, the cause of the erection problems probably is not physical.

The NPT test may also be called the stamp test or the rigidity test.

Intracavernosal injection test

During this test, the doctor injects a medicine (usually alprostadil) into the side of the penis to make an erection. This is called an intracavernosal injection. A similar medicine may also be placed into the urethra camera.gif, the tube through which urine leaves the penis. This is called an intraurethral injection. The fullness of the erection and how long the erection lasts are measured.

Doppler ultrasound test

Doppler ultrasound (also called color duplex Doppler) uses a handheld tool passed lightly over the penis. The tool uses reflected sound waves to estimate the speed and direction of blood as it flows through a blood vessel. The sound waves go to a computer that changes the sounds to colors that are overlaid on a picture of the blood vessel. This shows the speed and direction of blood flow. You may need to have medicine injected into your penis (intracavernosal injection) to cause an erection before the Doppler test is done.

The results of your tests may show which kind of treatment is a good choice for you.

dplink.gif Erection Problems: Should I Try Injection Treatments?

Health Tools

Health Tools help you make wise health decisions or take action to improve your health.


Decision Points focus on key medical care decisions that are important to many health problems.

Erection Problems: Should I Take Medicine? Erection Problems: Should I Try Injection Treatments?

Why It Is Done

Tests for erection problems are done to help find whether the cause of an erection problem is physical, psychological, or a combination of both.

Physical conditions that may cause erection problems include:

  • Problems with the nerves of the penis. Conditions such as multiple sclerosis or diabetes may cause nerve damage that affects a man's ability to have an erection. Also, surgery, injury, or radiation treatment to the pelvic area may cause damage to the nerves of the penis.
  • Problems with the blood vessels that supply blood to the penis camera.gif. Conditions such as hardening of the arteries (atherosclerosis) may make it difficult for a man to have an erection. Activities such as long-distance bicycle riding on a hard, narrow saddle may increase a man's risk for having an erection problem.
  • Low levels of hormones, such as testosterone or thyroid hormones.
  • Side effects of medicines, such as medicines taken for high blood pressure (hypertension) or depression.
  • The use of tobacco, alcohol, or illegal drugs.

Psychological tests may be needed if no physical cause is found for an erection problem. Psychological causes of erection problems may include:

  • Anxiety about sexual performance.
  • Relationship problems.
  • Stress.
  • Depression or grief.
1 | 2 | 3 | 4 | 5 | 6 | 7

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.

Today on WebMD

handsome midadult man
11 tips to protect your erection.
man and woman on beach
How much do you know about ED?
stress in bed
Things that can deflate erections.
senior couple hugging
How medications work.
concerned man
stress in bed
Life Cycle of a Penis
Mens Body Problem
bored man
Lamm Erections Over Life
Food Men 10 Foods Boost Male Health
senior couple hugging

WebMD Special Sections