How Is ED Diagnosed? Tests, Questions and What Happens Next

ED is diagnosed mainly by conversation, not by testing. A prescriber asks about the pattern of the difficulty, your medical, and your current medicines, then checks a small number of basic measurements to look for possible contributing factors. For most men there is no need for imagining or immediate specialist referral.

That works because erectile dysfunction is a symptom rather than a single underlying disease. The assessment therefore asks two questions at once: does the pattern fit ED, and what might be contributing to it? The history answers the first, while measurements, examination where appropriate, and your medical history help with the second.

This page explains the criteria used, the questions you will be asked, which tests are done and why, how physical and psychological causes are told apart, and when an online assessment is enough.

Key things to know

• NICE defines erectile dysfunction as the persistent inability to attain and maintain an erection. Occasional difficulty does not meet that definition.
• Most of the diagnosis is history taking. Tests look for the cause rather than confirm the label.
• The assessment may include blood pressure, cholesterol, blood glucose or HbA1c, a review of your medicines, and testosterone where clinically indicated.
• Your prescriber may ask about morning or spontaneous erections because changes in their frequency or pattern can provide useful information alongside the rest of your history.
• NICE does not publish score bands defining mild, moderate or severe ED, despite those terms appearing widely online.
• Some trials cited by NICE required erectile dysfunction to have been present for at least 6 months, but this was a trial eligibility criterion rather than a diagnostic rule.
• ED medicines are not specifically listed among the medicine categories requiring the additional safeguards described by the GPhC, but online pharmacies must still gather enough information to make a safe and appropriate prescribing decision.

How is ED diagnosed?

Through a structured history, a short physical check where appropriate, and basic blood and blood pressure measurements. There is no single test that diagnoses erectile dysfunction, because the diagnosis of ED is clinical. Diagnosing ED is therefore primarily a clinical assessment supported by appropriate measurements and, where indicated, examination or investigations.

A prescriber works through three things. Does the pattern meet the definition, or is this normal variation. Is there a physical cause to find, particularly a cardiovascular or metabolic one. And is there anything that makes treatment unsafe.

That third question is why the assessment includes items that seem unrelated to erections, such as chest pain on exertion or the exact name of your heart medicine. Those answers change what can be prescribed.

What are the ED diagnosis criteria?

The criterion is persistence. NICE describes erectile dysfunction as the persistent inability to attain and maintain an erection, which sets a threshold that occasional difficulty does not cross.

There is no official UK figure for how long "persistent" must be. The NICE evidence summary on avanafil records that trial participants had "mild to severe erectile dysfunction of at least 6 months duration". That is a trial entry requirement rather than a diagnostic rule, but it shows how the concept is measured in practice.

There is no fixed UK duration that must be reached before an assessment can be made. A persistent or recurring pattern is more important than a specific number of months, and a shorter history may still warrant assessment when there is an obvious trigger or concerning symptom.

What does an ED diagnosis mean?

The ED diagnosis meaning is narrow. It means a prescriber has judged your difficulty persistently rather than occasionally, and is worth investigating. An erectile dysfunction diagnosis describes a symptom pattern, not your general health and not a permanent label.

Two things it does not mean. It does not mean the cause has been identified, which is a separate finding. And a diagnosed ED is not a fixed condition, since many contributors are modifiable through lifestyle changes and medical treatments.

One important aspect it often does mean. The NICE evidence summary notes that erectile dysfunction may be an early manifestation of coronary artery and peripheral vascular disease, so a diagnosis is also a prompt to have cardiovascular risk assessed and underlying health conditions evaluated.

Because ED can share risk factors with cardiovascular disease and diabetes, an assessment may also identify previously unrecognised health or cardiovascular risk factors.

What will the doctor ask about ED?

Expect eight areas of questioning, most about pattern and history rather than anything invasive. Knowing the list makes the appointment shorter and the answers better.

• When it started, and whether it began suddenly or gradually. Sudden onset can suggest a recent trigger, while gradual onset may occur with longer-term health, medication or psychological factors.
• Whether it happens every time or varies. Consistent symptoms may increase suspicion of a physical contributor, while variation between situations can provide clues about psychological or situational factors. Neither pattern proves the cause on its own.
• Whether morning erections still occur, and whether they have changed.
• Every medicine and supplement you take, including anything bought without a prescription.
• Your medical history, particularly diabetes, high blood pressure, high cholesterol, heart problems and any prostate surgery or treatment.
• Cardiovascular symptoms: chest pain, breathlessness on exertion, palpitations, or leg pain when walking.
• Lifestyle factors: smoking, alcohol intake, physical activity, weight and sleep.
• Mood, stress and anxiety, because these affect the same nerve signalling.

NICE maintains an indicator on asking men with diabetes about erectile dysfunction, so this is expected to be raised rather than avoided. NICE guidance states it is "important that it is discussed in a sensitive manner which allows patients to voice their concerns in a safe and supportive environment".

Why they ask about morning erections

Morning or spontaneous erections can provide useful information about your overall erectile pattern, but they do not by themselves distinguish a physical cause from a psychological one. Your prescriber may ask whether they have changed, whether they still occur, and whether the change happened around the same time as your other symptoms.

Sleep quality, stress, alcohol, medicines and other factors can influence spontaneous erections, so the pattern needs to be considered alongside your wider medical and sexual history rather than treated as a diagnostic test.

Is my ED physical or psychological?

Certain patterns can provide clues about whether physical, psychological or situational factors may be contributing, but no single feature can reliably establish the cause.

For Example:

These are patterns rather than diagnoses, and mixed pictures are the most common finding. A physical cause can begin during a stressful period, and worry about it adds a psychological layer on top. That is why self assessment stops being reliable beyond this point.

What tests are done for ED?

A small number, and they look for causes rather than confirming the diagnosis. The standard set is quick and inexpensive.

The first four are things most adults should have measured anyway, which is the practical argument for going: the assessment doubles as a general health check.

Blood tests for erectile dysfunction

Expect a small panel rather than an extensive screen: a lipid profile for cholesterol, HbA1c or fasting glucose for diabetes, and in some cases a morning testosterone level. Those three appear because NICE identifies diabetes among the physical causes and names high cholesterol and metabolic syndrome among the risk factors erectile dysfunction shares with cardiovascular disease.

Blood tests may also include thyroid hormone levels to check for hormonal imbalances that can affect erectile function. Urine tests may be considered where there is a specific clinical reason, such as assessing diabetes or kidney-related problems.

What blood tests cannot do is confirm erectile dysfunction, because there is no specific marker for it. A normal set of results does not mean the difficulty is imagined. It means the common metabolic and hormonal causes have been excluded.

In selected cases, a penile duplex ultrasound may be recommended to assess blood flow and help identify vascular causes of ED.

These investigations can help identify or rule out some physical contributors, while the history and overall assessment help determine whether psychological or situational factors may also be involved.

Early diagnosis of ED through these tests can also prompt assessment and management of underlying conditions.

Testosterone is measured on a morning blood sample and is not routine for every man with erectile dysfunction. It may be considered when symptoms or the clinical history suggest possible testosterone deficiency, particularly when erectile symptoms occur alongside features such as reduced libido or other symptoms of hormonal deficiency. Timing matters because levels are highest in the morning, and an afternoon sample can read low in a man whose levels are normal.

Two caveats. Low testosterone is a less common cause than vascular problems, so a normal result is the usual outcome. And treating a confirmed deficiency is a prescriber led decision requiring monitoring, not something to arrange through a supplement.

ED physical examination

An examination is not always necessary, and when required, it is usually straightforward. It typically covers blood pressure, pulse, weight, and where indicated a check for anatomical causes such as curvature or scar tissue.

Whether it is needed depends on the history. If that points clearly at a medicine or at cardiovascular risk factors, it may add nothing. If there is pain, a change in shape or an unexplained finding, it becomes important.

Tests you probably will not need

Most men are diagnosed without any of the following, so being offered them without explanation is worth questioning:

• Ultrasound imaging of penile blood flow
• Overnight monitoring of erections
• Specialist vascular studies
• Hormone panels beyond testosterone
• Any test bundled with a treatment you have not yet been assessed for

These tests are generally reserved for selected cases where the history, examination or response to treatment suggests that further investigation is needed.

ED questionnaires and self assessment

Questionnaires measure severity and track change. They do not make the diagnosis. They give a number comparable before and after treatment, which is why they appear in trials.

What is the ED questionnaire used in research?

The most widely used is the International Index of Erectile Function, shortened to IIEF. The NICE evidence summary on avanafil describes it as "a 15-item questionnaire, self-administered measure of erectile function" covering several domains, one being erectile function itself, assessed by 6 of the 15 items. That domain is the part quoted in trial results, and NICE records that trial eligibility required "an International Index of Erectile Function (IIEF) erectile function domain score of 5 to 25".

A shorter version is sometimes used in consultations. Either way the questionnaire supports an assessment rather than replacing it, because a score cannot tell a prescriber whether your blood pressure is raised or which medicines you take.

Mild moderate severe ED: what the scores do and do not say

Those terms are used clinically and appear throughout NICE trial descriptions, but NICE does not publish score bands defining where mild ends and moderate begins.

That matters because many pages present specific IIEF cut-offs as official UK classification. They are not drawn from NICE or MHRA guidance. So a questionnaire score is a snapshot useful for tracking change, not a diagnosis, and it does not determine what treatment is appropriate. Treatment suitability depends on an individual clinical assessment.

Importance of medical and sexual history in diagnosing ED

Taking a thorough medical and sexual history is essential when assessing erectile dysfunction. This includes questions about lifestyle factors such as smoking, alcohol consumption, recreational drugs and physical activity, as well as mental health factors that may contribute. Understanding sexual relationships and any changes in sexual desire can provide additional information about possible psychological, situational or physical contributors.

Role of physical exam and tests in identifying underlying physical cause

A physical exam focuses on cardiovascular health indicators like blood pressure and pulse, as well as anatomical assessments of the penis for curvature or scar tissue.

Prescription drugs review is critical, as some medications can cause or worsen erectile dysfunction. Blood tests may include testosterone where clinically indicated.

In selected cases, specialist investigations such as penile duplex ultrasound may be used to assess vascular function. Intracavernosal injection may also be used as part of specialist assessment in some circumstances. These tests are not routinely required for an initial ED assessment.

Differentiating psychogenic ED from physical causes

Psychological or situational factors may be more likely when erections are preserved in some circumstances but difficulties occur in others, including when morning or spontaneous erections remain present. However, these patterns are not diagnostic, and physical and psychological factors often coexist.

Additional diagnostic tools and clinical trials

While most cases do not require advanced testing, some may benefit from clinical trial participation for emerging erectile dysfunction treatments. These include novel therapies aiming to improve erectile function by targeting underlying vascular or neurological issues.

Summary

Diagnosing erectile dysfunction involves a detailed medical and sexual history, appropriate physical examination where indicated, and targeted tests or measurements when needed to identify contributing factors.

Do I have erectile dysfunction? An ED self assessment

Work through five questions honestly. This ED self assessment is not a diagnosis, but it will tell you whether an appointment is worth booking.

• If the difficulty is persistent or recurring and happens on most or all occasions, it is worth discussing with a healthcare professional.
• Does it happen on most or all occasions, rather than only some?
• Have your morning erections changed over the same period?
• Did anything change around the time it started: a new medicine, a stressful period, increased drinking, disrupted sleep?
• Do you have raised blood pressure, diabetes, raised cholesterol, or do you smoke?

Yes to the first two suggests the definition is met. Yes to the third or fifth raises the likelihood of a physical contributor, and yes to the fourth points at something potentially reversible. Some men delay seeking medical advice about erectile difficulties, which can mean underlying causes are not assessed promptly.

How long does it take to diagnose ED?

In straightforward cases, the initial assessment can often be completed in one appointment, with any blood-test results following later. If further assessment is needed, the process may take longer.

Trialling a medicine switch, or addressing alcohol or sleep, needs several weeks. Those are treatment timelines rather than diagnostic ones.

Can ED be diagnosed online?

An online assessment may be appropriate for some men with straightforward erectile difficulties, provided the service gathers enough information to make a safe and appropriate clinical assessment. Some people will need face-to-face assessment, examination or further investigations.

The GPhC's guidance for registered pharmacies providing pharmacy services at a distance, updated in February 2025, requires that staff "get all the information needed so they can check that the supply is safe and appropriate", and "check that the person receiving pharmacy services is who they claim to be by carrying out an identity check appropriate for the medicine being supplied".

The same guidance states that "some medicines are not suitable to be prescribed by a questionnaire model alone", and lists the categories requiring extra safeguards: antimicrobials, medicines liable to misuse, medicines with a high overdose risk, long term condition medicines, pregnancy prevention programme medicines, weight management medicines and black triangle medicines.

Erectile dysfunction medicines are not among those categories. That is the regulatory basis on which a robust online consultation is an accepted route for this condition.

What a legitimate online ED consultation involves

The same ground a face to face assessment covers. A private ED assessment should ask about your symptoms and their pattern, heart conditions and blood pressure, every current medicine with specific questions about nitrates, liver and kidney health, and any eye conditions or previous vision loss. You should also be able to be declined.

For some pharmacist-supplied ED medicines, MHRA guidance and product information set out specific circumstances in which supply is inappropriate or requires referral. These can include certain cardiovascular conditions, uncontrolled hypertension, severe liver or kidney problems, previous vision loss associated with treatment, and important medicine interactions.

Two interactions carry specific rules. Nitrates and nitric oxide donors, such as glyceryl trinitrate or nicorandil, must never be combined with these medicines because the combination "can lead to a dangerous fall in blood pressure". Alpha blockers also require particular caution and should be assessed by an appropriate prescriber before a PDE5 inhibitor is supplied.

A service that asks none of this, or approves everyone, is not assessing anyone. You can check your eligibility for erectile dysfunction treatment through an online consultation with UK registered prescribers.

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When an online assessment is not enough

An online route is not the right starting point in several situations:

• Your blood pressure, glucose or cardiovascular risk has not previously been assessed and the service cannot obtain the information it needs.
• You have chest pain, breathlessness on exertion, or leg pain on walking.
• You take nitrates, alpha blockers, or a medicine you are unsure about.
• The difficulty came with pain, a change in shape, or an unexplained physical finding.
• You have had prostate surgery or pelvic treatment.
• You want the cause investigated rather than the symptom managed.

In those cases the assessment needs measurements and sometimes examination. An online consultation can form part of the picture, but not all of it.

ED diagnosis and treatment: what happens next

Once a cause has been identified or excluded, treatment follows one of three paths, and none begins with a tablet by default.

• Address a reversible cause. A medicine switch, reducing alcohol, restoring sleep, or treating raised blood pressure or blood glucose. NICE recommends addressing appropriate lifestyle factors and other possible causes alongside treatment where relevant.
• Start drug treatment. NICE describes first line drug treatment as an oral PDE5 inhibitor: avanafil, sildenafil, tadalafil or vardenafil. For how these work, see our guide to what an ED pill is and how ED pills work.
• Both together, the most common outcome, because the cause takes months to shift while the symptom can be managed now.

A single unsuccessful attempt does not necessarily mean a PDE5 inhibitor will not work, as response can vary between individuals and correct use may take some adjustment.

Treatment suitability depends on an individual clinical assessment, and these medicines should only be used under the supervision of an appropriately qualified prescriber. Results vary between individuals.

When to see a doctor about ED

Arrange an assessment if erection difficulties are persistent or recurring, particularly if they are affecting your sexual life or causing concern. Seek urgent medical attention if any of the following apply:

• Chest pain, breathlessness or palpitations, especially on exertion.
• Pain in the calves or thighs when walking that eases with rest.
• Difficulty that began within weeks of starting or changing a medicine.
• Unexplained weight loss, excessive thirst or frequent urination alongside it.
• Persistent low mood, or thoughts of harming yourself.
• Any change in the shape or curvature of the penis, or pain.
• An erection lasting more than four hours, known as priapism, which needs urgent medical attention.

The first two matter because of the vascular overlap already described. A clinic blood pressure reading of 180/120 mmHg or higher warrants urgent clinical assessment, particularly if there are symptoms suggesting acute target-organ damage.

On the third, a Drug Safety Update published on 11 May 2026 strengthened MHRA warnings for finasteride and dutasteride, prescribed for prostate enlargement and hair loss, stating that erectile dysfunction is among the side effects that may persist even after treatment is stopped. Never stop a prescribed medicine on your own.

One final reason not to skip assessment. In February 2026 the MHRA reported seizing around 19.5 million doses of illegal erectile dysfunction pills between 2021 and 2025, stating that such products "may contain no active ingredient, the wrong dose, hidden drugs or toxic ingredients".