Erectile dysfunction tests and diagnosis: What to expect at the doctor’s office

If the word "tests" makes you want to close this tab, you're not alone. Most men can be assessed for erectile dysfunction (ED) through a talk about their symptoms and medical history, plus a physical exam (AUA, 2018).

Doctors diagnose ED mainly from your medical and sexual history and a physical exam (AUA, 2018). Blood tests can help find health problems that may be adding to it, and imaging is only needed in some cases.

Your first assessment may include a questionnaire, such as the International Index of Erectile Function (IIEF) or the Sexual Health Inventory for Men (SHIM). It may also include a morning testosterone test and checks for heart and blood vessel risk factors (AUA, 2018). A doctor or other qualified healthcare provider makes the actual diagnosis. For the bigger picture on what causes ED and how it's treated, start with our full guide to erectile dysfunction.

How do doctors diagnose erectile dysfunction?

An ED assessment usually begins with your medical and sexual history, followed by a physical exam and any tests or referrals your doctor thinks you need (AUA, 2018); (NIDDK, 2024). How many tests you have, and in what order, depends on your symptoms, your history, and what the exam finds. If you haven't had that first appointment yet, here's what to expect from that first conversation.

An ED check-up can include:

• Your history. Your doctor asks about your sexual, medical, and mental health history, and may use a questionnaire to score your symptoms.
• A physical exam. A check for signs of health problems that could be affecting your erections.
• Blood tests. These look for conditions that may be playing a part, like low testosterone or diabetes.
• Imaging or specialist tests. These are only for some men, usually when a specific problem is suspected.
• A referral, if needed. This could be to a specialist for the physical side, the psychological side, or both.

Diagnosis works best as a two-way conversation. Your doctor should explain why they're suggesting each test, and you can ask about anything that isn't clear. Doctors call this shared decision-making, which means you and your doctor decide on next steps together (AUA, 2018).

The history and questionnaire part of an ED diagnosis

Expect questions about what's changed, when it started, and how it's affecting your life. Your doctor may also ask whether you still get erections in the morning or when you masturbate, how your sex drive is, and whether the problem happens every time or only in some situations (AUA, 2018). These details help show what might be behind your ED.

They'll also ask about your general health and mood. They'll want to know about any prescription medicines, supplements, alcohol, recreational drugs, and nicotine (from cigarettes, vapes, or pouches) (NIDDK, 2024). All of these can affect erections, so honest answers help your doctor find the cause.

The IIEF is a 15-question tool covering 5 areas of sexual function, and 6 of its questions focus on erections. The SHIM is a shorter, 5-question version (also called the IIEF-5) that's often used instead (AUA, 2018). Both help measure how severe erection difficulties are and track changes over time, but they don't replace a doctor's assessment.

Score ranges as given in the American Urological Association (AUA) guideline (AUA, 2018).

Show up with a questionnaire already filled in, and you've given your doctor a useful head start. If you don't have time for that, don't worry. Your doctor will get what they need either way.

Your doctor may also ask whether you feel pressure to perform, or find yourself distracted by worry during sex. This is sometimes called performance anxiety, where worrying about your erection makes it harder to relax and enjoy sex. It can add to erection difficulties alongside other factors.

What a physical exam for ED involves

A physical exam for ED checks for signs of blood vessel, nerve, hormone, or penis problems that could be involved (NIDDK, 2024).

Depending on your history, this might include:

• Blood pressure and pulse checks, to look at your heart and blood vessel health. Your doctor may also measure your weight or waist to check for related health risks (EAU, n.d.).
• A genital exam, to check for changes in the penis, like lumps, scarring, unusual curving, a tight foreskin, or signs of injury.
• A general physical exam, to look for signs of health conditions that may affect erections. Blood tests may also be needed to check for diabetes or heart risk factors.

Not every doctor runs every check. They use your history to decide what's relevant to you.

What blood tests are used to diagnose ED?

No single blood test diagnoses ED, but blood tests can find conditions that may be contributing. Doctors often recommend a morning testosterone test to check whether low hormone levels may be playing a part (AUA, 2018).

Testosterone is usually highest in the morning, which is why the test is done then. One low result isn't enough to confirm low testosterone, so doctors repeat the test and look at your symptoms before making that diagnosis (AUA, 2018).

The European Association of Urology (EAU) also recommends blood sugar and cholesterol tests if you haven't had them in the past year (EAU, n.d.). Depending on your history, your doctor might check:

• Blood sugar (fasting glucose or HbA1c, a measure of your average blood sugar over the past few months), to check for diabetes or prediabetes, which can contribute to ED.
• Cholesterol and other blood fats (a lipid profile), to look at heart risk factors that may also contribute to ED.
• Thyroid function, since thyroid problems can affect erections.
• Kidney function, if there are signs or risk factors for kidney disease, which can also affect erections (AUA, 2018).

Some of these tests need you to skip breakfast and some don't. An HbA1c test doesn't need fasting, and a morning testosterone test is ideally done before you eat (EAU, n.d.). Your doctor will tell you how to prepare, and they'll only order what applies to you.

Imaging and specialist tests for ED

Most men don't need imaging or specialist tests. They're usually only used in some cases, like when a blood vessel problem is suspected, after a penis injury, when the penis has changed shape, or when standard treatment hasn't worked (AUA, 2018). Penile duplex ultrasound is a specialist imaging test that checks blood flow to the penis when a blood vessel problem is suspected.

Here's how the main parts of an ED assessment compare. Your doctor will choose what fits you, so most men won't need every step.

Sources for this table: (AUA, 2018); (EAU, n.d.).

Older vein-leak tests, like cavernosometry and cavernosography, still get mentioned online, but the AUA guideline notes they're seldom performed today (AUA, 2018).

Can you test for erectile dysfunction at home?

At-home blood tests can measure some health markers, like testosterone, but they can't diagnose ED or find all its possible causes. If you use one, choose a reputable provider, and still book a medical assessment.

A doctor can choose the right tests for you. They can also read the results alongside your symptoms, your exam, and your medical history.

You might also come across the old "stamp test," where a strip of stamps is wrapped around the penis overnight to see if the perforations break by morning. It isn't a reliable way to diagnose ED. Unlike clinical nighttime erection testing, it can't measure how firm an erection is or how long it lasts.

If you're trying to figure out how to tell whether your ED is more likely physical or psychological, that's a good next read.

Why an ED diagnosis matters beyond your sex life

ED can be an early warning sign of heart and blood vessel disease, sometimes showing up before other symptoms do (AUA, 2018). Doctors call ED a risk marker. It means your heart health is worth checking, and it doesn't mean you have heart disease.

When ED comes from a blood flow problem, one explanation is that the arteries in the penis are smaller than the ones around the heart. Narrowing can affect erections before it causes heart symptoms (Montorsi et al., 2006). This mainly applies to blood-flow-related ED, so not every erection problem is a sign of heart trouble.

ED and heart disease share several risk factors, including nicotine use, diabetes, high blood pressure, high cholesterol, obesity, and not being physically active (AUA, 2018). Depression and anxiety can also contribute to erection difficulties. If your check-up turns up one of these, treating it can help your overall health and may help your erections too.

Getting checked can help find underlying health conditions, show what's contributing to your erection difficulties, and point you to the right treatment. Understanding the physical and psychological causes of ED is a good next step once you know what your doctor found.

What happens after your ED diagnosis

Once your doctor has a clearer picture, they'll talk you through next steps. Depending on what's contributing to your ED, they may suggest a urologist, a mental health professional, a specialist sex therapist, or a mix of support (NIDDK, 2024).

Healthy eating and regular physical activity can improve your overall health. They may also help erections, especially when heart or lifestyle factors are involved (AUA, 2018).

Physical and psychological factors often overlap, so treatment may need to address both at the same time. You can read more about psychological erectile dysfunction and the full range of ED treatment options.

Mojo focuses on the psychological side. Some studies show that as many as 30% of men under 40 have had erection difficulties, though estimates vary a lot between studies (Nguyen et al., 2017). Psychological factors are a common and important cause, particularly in younger men.

The Erection Reset was built by Dr. Shannon Chavez, a licensed clinical psychologist and AASECT-certified sex therapist. It's designed to help men address performance anxiety, rebuild sexual confidence, and develop healthier responses to erection difficulties.

Mojo doesn't diagnose, treat, or replace a doctor's evaluation. If you haven't talked to a doctor yet, that's a good first step. If performance anxiety or other psychological factors are affecting your erections, the program can offer support alongside the right medical care.

When should you see a doctor about ED?

It's worth seeing a doctor if erection problems keep happening or are worrying you. A doctor can help work out the cause and what to try next.

Get emergency medical help right away if:

• You have an erection that lasts more than 3 to 4 hours, even without sexual stimulation (NHS, n.d.).
• You have sudden, severe pain in your penis after an injury, especially with a cracking or popping sound and swelling (BAUS, n.d.).

Mojo provides expert-led educational content. It doesn't diagnose, treat, monitor, or cure ED or any other medical condition. Always talk to a qualified doctor or healthcare provider about your specific situation.