How Erectile Dysfunction Is Diagnosed

Table of Contents
View All
Table of Contents

If you or your loved one is seeking treatment for erectile dysfunction (ED), you may be feeling overwhelmed, anxious, or discouraged. But the more knowledgeable you become about the condition, which includes its diagnostic evaluations, exams, and procedures your doctor may recommend, the quicker you can regain a sense of control.

After all, ED is treatable; once you understand what’s going on with your body, you’ll be armed with information to choose a treatment approach that’s best for you.

Erectile dysfunction diagnosis
Illustration by Joshua Seong. © Verywell, 2018.

Self-Checks and At-Home Testing

You have options for performing at-home tests, either on your own or using a device recommended by your doctor.

Nocturnal Penile Tumescence (NPT) Stamp Test

When sleeping, it’s common for a man to average anywhere from three to five erections per night lasting 25 to 35 minutes, according to the National Health Service (NHS) in the United Kingdom.

Researchers don’t fully understand why night-time erections occur, but they believe they’re closely linked to the REM phases of your sleep cycles. Night-time erections can be an indicator that your reproductive system is functioning properly.

For people with ED, there may be an absence of night-time erections. If you’re uncertain as to whether you’re having erections while sleeping, you can try a self-test, as stated by the University of California, San Francisco Medical Center (UCSFMC). The test is called the nocturnal penile tumescence (NPT) stamp test, and it involves wrapping four to six postage stamps of any variety around your penis before you go to sleep and noting changes upon waking up.

Although this specific self-test is considered outdated, if you’ve never discussed ED with a healthcare provider before, it may give you with some talking points to initiate a conversation. Also, there are no risks involved when the self-test is performed correctly.

How to Do a NPT Stamp Test

Here's how to perform the NPT, as outlined by UCSFMC:

  • You’ll need a strip of four to six postage stamps for each night, and you’ll perform the self-test three nights in a row.
  • Wear brief-style underwear with a fly.
  • Position the penis so that it’s through the fly, and keep most of your pubic hair inside the briefs.
  • Using the stamps, make a tight ring around the shaft of the penis. Make sure the stamps overlap so that you can moisten the top one and seal it over the bottom one.
  • Allow the stamps to dry for a minute or two, and reposition the penis back inside the briefs. The underwear will help to hold the stamps in place while you sleep. At first, the stamps may feel a bit strange or uncomfortable.
  • When you awaken, check to see if your stamp ring has torn along any of the perforations. If you awake in the middle of the night and notice you have an erection, UCSFMC recommends checking it and assessing its firmness.

While the stamp self-test may be able to provide you with some information as to whether or not you’re having nightly erections, it can’t provide details as to the quality or duration of them. Ultimately, if you suspect ED, you should make an appointment to see your doctor.


Your doctor may offer you more up-to-date options for at-home testing, like a portable home device called the RigiScan. This device is one you can take home with you and it provides more detailed information, including penile rigidity and engorgement, measured by loops attached to the penis before sleeping.

The data is stored on the portable computing device and can be reviewed and printed on command. Overall, the device is easy to use and requires little training. You should discuss the feasibility and costs with your provider.

Labs and Tests

When you see your doctor, they’ll gather your health history, ask additional follow-up questions regarding your sexual health, and perform a physical exam. In some instances, this may be all the doctor needs to make an accurate diagnosis of ED and provide you with treatment options.

However, if the doctor believes an underlying condition may be contributing to ED, they might suggest additional testing or an appointment with a specialist for the following.

A Physical Examination

The doctor may examine your penis, testicles, patterns of hair loss on certain parts of your body, or the presence of gynecomastia—a condition where the breast tissue in a man swells in response to hormone imbalances.

Your doctor may also examine whether the sensation to the penis and testicles is intact and if there’s adequate blood flow to the area.

Also, your physical assessment could include a rectal exam to evaluate your prostate as well as the tone of the muscles of the pelvic floor. Finally, your doctor might check out your heart and lung function to help determine the best course of action regarding treatment.

Erectile Dysfunction Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Man

Blood Tests

If it’s been a while since you’ve seen a doctor, they may choose to run some basic blood work such as a complete blood count (CBC) and a comprehensive metabolic panel (CMP). The data collected from these blood tests provide your doctor with an overview of how your body is functioning.

Other blood panels your doctor may request include testosterone levels (most accurately done between 8 am and 11 am), a thyroid panel, or other more specific tests that provide insight into your unique situation. Discuss what your doctor hopes to gather from this information.

Urine Test 

Underlying illnesses like diabetes can be responsible for causing or worsening ED. Urine tests screen for the presence of diabetes or other health conditions. If your doctor suspects you have one of these illnesses, they may recommend a urine test or urinalysis.   

Mental Health Evaluation 

Psychological factors like depression or anxiety can cause ED. As a result, your doctor might ask you a series of questions about your mental health. Just try to answer the questions honestly and to the best of your ability so that your doctor can make appropriate treatment recommendations to support your emotional health and well-being.


If your doctor needs to examine the blood flow to the penis further, they’ll likely order an ultrasound, which could also involve an injection of medication (intracavernosal, which means into the penis) of medication (such as prostaglandin E1 or Trimix which is a mixture of papaverine, phentolamine, and prostaglandin).This same medication can be used for treatment if oral medications are not effective.

Ultrasound technology uses sound waves to create images of what’s going on in your body. A trained technician (possibly a urologist or radiologist) will hold a small instrument over the blood vessels that supply the penis and gather a series of pictures to identify if there’s diminished blood flow (arterial insuffiiciency) or venous leakage (blood not maintained in penile veins during erection).

Typically, ultrasounds are outpatient tests, and the procedure isn't painful.

Differential Diagnoses

In many instances, once the doctor has reviewed any relevant medical and sexual history and performed a physical exam, they can make a preliminary diagnosis of ED. Some physicians might choose to prescribe a trial dose of an oral medication to treat ED—medications are generally safe for healthy men.

However, if your symptoms of ED are accompanied by another condition like diabetes, high blood pressure, or prostate problems, your doctor will need to take a more in-depth look at your particular situation to determine a plan of care.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Health Service. Sexual Health: 5 penis facts. Updated April 6, 2018.

  2. Becher E., Bechara A. (2011) Making the Diagnosis of Erectile Dysfunction. In: McVary K. (eds) Contemporary Treatment of Erectile Dysfunction. Contemporary Endocrinology. Humana Press. doi:10.1007/978-1-60327-536-1_6

  3. Elhanbly S, Elkholy A. Nocturnal penile erections: the role of RigiScan in the diagnosis of vascular erectile dysfunction. J Sex Med. 2012;9(12):3219-26. doi: 10.1111/j.1743-6109.2012.02954.x

  4. Yafi FA, Jenkins L, Albersen M, et al. Erectile dysfunction. Nat Rev Dis Primers. 2016;2:16003. doi:10.1038/nrdp.2016.3

  5. National Institute of Diabetes and Digestive and Kidney Diseases. Diagnosis of Erectile Dysfunction. Published July 2017.

Additional Reading