It’s also known as the nocturnal penile tumescence (NPT) stamp test.
The test is done to confirm that you experience erections at night. Men who have a normal physiological erectile function experience an erection during normal sleep.
According to the University of California, San Francisco Medical Center, the average healthy pubescent male will have between three to five spontaneous erections a night, lasting 30 to 60 minutes each.
Physical, emotional, or mental problems can lead to ED. This test helps determine if your ED is caused by physical problems.
The test is considered outdated. There are a variety of ways that it can be conducted. More reliable tests, such as NPT testing using a RigiScan, are now available.
A RigiScan is a portable home device used to evaluate the quality of nocturnal penile erections. The portable battery-powered unit is strapped around the thigh. It’s equipped with two loops that are connected to a direct-current torque motor.
One loop goes around the base of the penis, and the other is placed below the corona, the area of the penis before the glans penis. Throughout the night, the machine repeatedly measures how much blood is in your penis (tumescence) and how well it can resist bending or buckling (rigidity).
This test can be repeated several nights in a row. The results from each night are stored on the machine so your doctor can download and analyze it.
The penile plethysmograph is another test that’s sometimes used to distinguish between physical and psychological ED. This device measures the erection of your penis as you view or listen to sexual material. This can include viewing pictures, watching pornographic slides or movies, or listening to sexually stimulating audiotapes. During the test, penile cuffs are attached to a pulse volume recorder (plethysmograph) that displays and records waves of blood to the penis.
These are just a couple tests that are used in place of the well-known stamp test, and they’re often more accurate. It’s also becoming increasingly difficult to find postage stamps (which are used in the test) that aren’t already sticky on the back.
The biggest benefit of the erection self-test is that it allows you to test yourself if you’re embarrassed to discuss the subject with your doctor.
You’ll need to buy four to six postage stamps. The denomination of the stamps doesn’t matter, but they should have dry glue on the back.
Stamps are the most convenient option, but there are other alternatives. If you don’t have stamps, you can use a strip of paper. The strip of paper should be 1 inch wide and long enough to go around the penis with a little overlap. The paper can be secured with a 1-inch piece of tape.
Abstain from alcohol or any chemical sleep aids for two nights before the test. These can prevent erections. You should also avoid caffeine to make sure you have a good night’s sleep.
Change into briefs or boxer brief underwear before you go to bed. Take enough stamps to circle the shaft of your penis.
Pull your flaccid penis through the fly in your underwear. Moisten one of the stamps on the roll and wrap the stamps around your penis. Overlap the stamps in the roll to ensure they’ll stay securely in place. It should be snug enough so the stamps break apart if you have an erection. Place your penis back inside your shorts and go to bed.
For best results, sleep on your back so the stamps aren’t disturbed by your movement.
Do this three nights in a row.
Check to see if the roll of stamps is broken when you wake up in the morning. You could have had an erection in your sleep if the stamps are broken. This could indicate that your penis physically functions properly.
There are no risks associated with an erection self-test.
Not breaking the roll of stamps in your sleep could be an indication that your ED is caused by a physical problem.
This test only indicates whether you’re capable of having an erection. It won’t explain why you’re having problems getting or maintaining an erection.
Failure to have an erection during sex may be psychological in nature, such as having depression. Make an appointment with your doctor if you’re having problems getting or maintaining an erection. Your doctor can screen you for depression or other psychological disorders and recommend you to a mental health professional for treatment.
Talk to your doctor if you regularly experience ED. Many men don’t feel comfortable talking about the subject, but you shouldn’t feel embarrassed. This is a fairly common condition, especially as you age.
Your doctor can help you confirm if your ED is caused by physical or psychological reasons. Talk therapy and pharmaceutical drugs are common treatments for ED.
Medically Reviewed by:
Published By: Healthline Networks, Inc.