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Erectile Dysfunction (ED) Tests: NPT, Venous Leak and More

Katelyn Hagerty

Reviewed by Katelyn Hagerty, FNP

Written by Geoffrey Whittaker

Published 10/26/2020

Updated 07/27/2023

Chances are, you’re well aware that your sex life is suffering some setbacks. Erectile dysfunction (ED) may have curbed your good times on occasion before — but if a pattern of flops and nonstarters colors your sexual history, you might already have a feeling something’s not right.

You’re not alone — ED is a common issue affecting men of all ages. According to the National Institutes of Health, around 30 million men in the United States are affected by erectile dysfunction to varying degrees.

Though erectile dysfunction can be frustrating and stressful, it’s usually treatable through the use of medication, lifestyle changes and other treatment options. But to get to the treatment part of ED, you have to first get diagnosed.

Self-testing for ED and other sexual health issues isn’t necessarily difficult. You can do some tests at home or simply log your sexual history of erectile dysfunction symptoms until you feel it’s time to talk to a healthcare provider. 

If you want to get your sex life back on track, an ED test might make things move a little faster.

Below, we’ll go over the most common types of tests and how they work, as well as what an ED doctor (or the staff of an ED clinic) can do to help you figure out what’s wrong downstairs. Some tests may help determine the cause of ED, while others might just help you know if you have ED at all.

In any case, these tools can help root out the health problems or hormonal problems affecting you so you can return to your previous glory.

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Before we dive into the details of ED tests, it’s important to understand why erections happen — because that’s what these tests look for.

Erectile dysfunction can occur for several reasons. Some ED is physical, meaning a physical factor, such as your cardiovascular health, affects your body’s ability to supply blood to the soft tissue of your penis.

Common physical causes of ED include high blood pressure, thyroid conditions and other medical conditions that affect blood flow, such as diabetes. Additionally, certain oral medications, like antidepressants, could contribute to ED.

Other cases of ED are psychological. If you have psychological ED, things like stress, low self-esteem or sexual performance anxiety may make it more difficult to get and maintain an erection, even when you’re sexually stimulated.

Here’s the thing: Unlike many other medical conditions — which can be accurately diagnosed using clinical tests — there’s no standardized test that can confirm whether or not you have erectile dysfunction and why it’s occurring. 

Urology experts look for anything from damage at the base of the penis and chronic issues affecting the blood vessels to malfunctioning penile implants and side effects of medications.

When you talk to a urologist or another healthcare provider about treating ED, they’ll likely discuss your symptoms with you to determine the best treatment. And there may not be an official “ED test” involved in the process of ED treatment.

Healthcare providers will perform physical exams to check for things that may contribute to erectile dysfunction, such as high blood pressure, high blood sugar or health issues affecting blood circulation.

But an erectile dysfunction test (or an erection self-test) can help figure out if you have physical or psychological causes of ED — sometimes. 

Tests used to evaluate ED include:

  • Blood work

  • Urine tests

  • Nocturnal penile tumescence (NPT) test

  • Nerve tests

  • Duplex ultrasound test

  • Venous leak test

Let’s dive into the details of these ED test types.

Blood Work

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One thing that might help your healthcare provider figure out what’s going on is blood work. They may order various blood tests or a sample of your blood to check for low testosterone levels and other hormone deficiencies, thyroid function, cardiovascular health issues, diabetes, liver and kidney function and other factors that could contribute to erectile dysfunction. 

After your healthcare provider orders these tests, they might refer you to a urologist for further evaluation.

The two most common types of blood tests include a complete blood count test (CBC test), which tests the levels of all types of blood cells in your body. The other is a blood sugar test, which measures the amount of glucose in your blood.

Others include a lipid profile, liver function tests and an HbA1c (hemoglobin A1C) test to screen for diabetes.

Urine Test

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While it’s not an incredibly common way of diagnosing ED, a urine test can reveal information about your hormone levels, kidney function, diabetes and other things that may contribute to erectile dysfunction.

These tests also look for factors like out-of-whack glucose levels or UTIs (urinary tract infections) that can contribute to erectile dysfunction.

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One of the oldest erectile dysfunction tests is the nocturnal penile tumescence test, also known as an NPT test.

We’re giving it a lot of text here because it’s commonly discussed — but before we get into the specifics, we want to be clear: The NPT test is outdated and not really very accurate.

But although it’s generally considered outdated (and isn’t perfectly accurate), the nocturnal penile tumescence test may help you work out whether your ED is caused by a physical factor or a psychological one.

The real value of NPT testing is confirming that you can get hard. This would tell you your sexual activity problems aren’t about sexual desire (i.e., possible low testosterone) or physiological issues but rather psychological, like anxiety or depression.

The NPT test works by monitoring your ability to get an erection while you sleep. All men with normal, healthy physiological erectile function will get spontaneous erections during sleep — a phenomenon referred to as nocturnal penile tumescence. Sometimes, this will spill over into your early waking hours too — what’s known as morning wood.

If the NPT test shows that you don’t get erections while sleeping, it could indicate that your sexual dysfunction symptoms are linked to a physical health factor. 

By itself, the NPT test doesn’t confirm that you have erectile dysfunction or that a certain factor is causing it. In fact, you’ll get almost as much information by just keeping a notebook to track your morning wood.

Erectile nerve tests are a specific kind of ED test designed to make sure you’re not failing to get hard because you can’t feel stimulation due to a lack of penis sensitivity. ED Nerve testing determines nerve sensitivity and function in your penis by sending small vibrations on the left and right sides of the penile shaft.

If the penis doesn’t react to the vibrations, nerve damage might be the cause of erectile dysfunction. A positive result could mean anything from a pinched nerve to neurological ED.

This can be due to spinal cord injuries or other nervous system issues. One particular kind of nerve test is the bulbocavernosus reflex or glans sensitivity test, which measures the nerve stimulation in your penis and spinal cord segments. To perform this test, pressure is applied to the glans penis, and anal contraction is observed.

Another type is the penile biothesiometry test. However, there’s no commonly agreed-upon format for this test, so it may look different from one professional to another.

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Duplex ultrasound testing (sometimes called doppler ultrasound testing) evaluates how effectively blood flows through your veins and arteries. This tells you if there’s a problem in your intracavernosal passages — the ones that fill with blood to make you hard.

This test may show tissue scarring, hardening of the arteries and other physical factors that contribute to erectile dysfunction.

During this test, a small needle is used to inject the penile tissue with a vasodilator. Next, an ultrasound wand is pressed to the side of the penis, allowing for echo waves to be collected.

Using the pitch of the echoes, the ultrasound can determine how effectively blood is flowing through your blood vessels.

If ultrasound tests come back positive, venous leak testing might help you locate the source of leaks — something that’s prevalent in ED at age 40.

Other tests that might be used to diagnose ED include cavernosography and dynamic infusion cavernosometry. These assessments can help locate and identify a venous leak (blood loss from the erectile tissue).

They could also involve vasoactive injection (injecting medication into the penis to induce an involuntary erection) or arteriography (imaging of blood vessels within the penis.

Thinking about getting an ED test? It might make the most sense to start by talking to a healthcare provider.

From the psychological causes to the physiological ones, there’s more value in talking to a healthcare provider sooner than later — especially since they’ll be able to get you started on treatments sooner than later (potentially without wasting time on tests). 

Treatment may look like medication in the form of sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) or avanafil (Stendra). Or it might take the form of online therapy for psychologically caused ED and sexual anxiety.

You may just need to learn how to relax during sex. Or maybe you need to improve your health and take better care of your heart.

Making certain changes to your lifestyle, such as exercising more, quitting smoking or losing weight, may help improve your erectile health and reduce the severity of your erectile dysfunction.

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Dealing with erectile dysfunction can be highly stressful. And if we remember anything from high school and college, it’s that tests usually just add to stress and anxiety. 

The good news is that you may not need to do any tests at all. Here’s what to keep in mind:

  • ED testing isn’t always necessary. Problems like heart disease, mental health issues, kidney disease and even injuries to the penis in the form of Peyronie’s disease can cause ED. But these conditions must be diagnosed by a healthcare professional.

  • Not all ED tests are very reliable (we’re looking at you, NPT).

  • Since erectile dysfunction is almost always treatable, you may need to determine the exact cause of your problems with help from a healthcare provider.

  • With medication, psychotherapy, lifestyle changes or a combination of different erectile dysfunction treatments, you should be able to recover your game.

  • If you have an underlying medical condition that may contribute to erectile dysfunction, such as hypertension (high blood pressure), your healthcare provider might recommend treating it first. That’s why it’s important to discuss your medical history and any current health conditions with your provider.

Ready to get to the heart of the matter? We can help. Our online therapy, medication and other resources are just a few clicks away, including some great options like chewable ED meds hard mints for the guy who needs fresh breath and a pocket free of pills. 

So skip the cramming for tests — unless your doctor orders one.

10 Sources

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  6. U.S. Department of Health and Human Services. (n.d.-a). Definition & Facts for erectile dysfunction - NIDDK. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/definition-facts.
  7. U.S. Department of Health and Human Services. (n.d.-a). Diagnosis of Erectile Dysfunction. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/diagnosis
  8. U.S. Department of Health and Human Services. (n.d.-a). Symptoms & Causes of Erectile Dysfunction. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). https://www.niddk.nih.gov/health-information/urologic-diseases/erectile-dysfunction/symptoms-causes
  9. Queremel Milani DA, Jialal I. Urinalysis. Treasure Island (FL): StatPearls Publishing. (2023). https://www.ncbi.nlm.nih.gov/books/NBK557685/
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