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.
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
Other tests that may be done as part of a physical exam
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
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)
- Intracavernosal injection test.
Nocturnal penile tumescence (NPT) test
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
- 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.
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, 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. For more information, see:
- Erection Problems: Should I Try Injection Treatments?