Erectile Dysfunction Tests and Diagnosis: What to Expect

Know what to expect from an ED assessment, which tests are useful and how to start doctor-reviewed care with Heracles.

Peter Grice
Medically reviewed by
Peter Grice, Clinical Lead
Table of contents

An ED assessment starts with your symptoms and health history. Blood pressure, a focused examination and selected blood tests help identify causes and guide treatment. Most men do not need a scan or invasive test.

Start confidentially with Heracles ED care. A doctor reviews your assessment, with additional blood tests, GP or urology consultations and psychosexual support available through our service.

At a glance

  • Symptoms and health history guide the assessment. No single blood test or scan proves or excludes ED.
  • Basic checks include blood pressure, weight or waist measurement, glucose or HbA1c, lipids and early-morning total testosterone.
  • Questionnaires record severity and response. Penile Doppler and night-time erection tests are reserved for selected or complex cases.

How is erectile dysfunction diagnosed?

The diagnosis is clinical. A man describes recurrent difficulty attaining or maintaining an erection that is adequate for satisfactory sexual activity. “Adequate” depends on the activity and the individual rather than a universal firmness target.

The clinician then considers three separate questions:

  1. Does the history fit erectile dysfunction rather than low libido, an ejaculation problem, penile pain or another sexual concern?
  2. Which physical, psychological, medication or relationship factors may be contributing?
  3. Is there an underlying condition or cardiovascular risk that needs investigation or treatment?

A remote consultation can cover much of the history and risk screening. It cannot replace a physical examination or laboratory testing when either is clinically indicated.

What questions will a clinician ask?

The assessment covers three areas:

  • Your erections and symptoms: when the problem began, whether it varies by situation or partner, firmness and duration, morning or night-time erections, masturbation, desire, arousal, ejaculation and orgasm. Mention pain, a curve, lump, shortening or injury.
  • Your health: conditions, operations, radiotherapy, medicines, supplements, smoking, alcohol and recreational drugs.
  • Your experience: mood, anxiety, stress, sleep, relationships and what you want from treatment.

Situational symptoms can suggest a psychological component; gradual difficulty in every setting can suggest a physical one. Mixed causes are common, so the whole picture matters.

What is the IIEF-5 or SHIM questionnaire?

The Sexual Health Inventory for Men (SHIM), also known as the five-item International Index of Erectile Function (IIEF-5), asks about confidence, firmness, maintenance and satisfaction over a defined period. A score can help describe severity, create a baseline and measure change after treatment.

The full IIEF covers additional domains including desire, orgasm and intercourse satisfaction. The Erection Hardness Score is a separate brief measure of rigidity. These tools support a clinical discussion; they do not distinguish vascular ED from anxiety, hormone deficiency or another cause.

Physical checks and tests at a glance

Assessment What it can identify How it is usually used
Blood pressure and pulseHypertension, hypotension or a cardiovascular concern relevant to treatment safetyPart of the basic assessment if not checked recently
BMI or waist measurementCardiometabolic risk contextUsed alongside history and blood tests, not as a diagnosis of ED
Glucose or HbA1cDiabetes or raised glucoseBasic metabolic testing when there is no recent result
Lipid profileRaised cholesterol and cardiovascular riskInterpreted as part of overall cardiovascular assessment
Early-morning total testosteronePossible testosterone deficiencyA low result requires clinical interpretation and usually confirmation, not immediate treatment
Focused genital examinationPeyronie’s disease, testicular change, anatomical abnormality or signs of hormone deficiencyPerformed when relevant and with consent
Penile Doppler ultrasoundBlood inflow and venous function after a vasoactive medicineSpecialist test for selected cases, not routine screening

What does the physical examination involve?

The extent of examination depends on the history. The EAU recommends a focused assessment of the genitourinary, endocrine, vascular and neurological systems. This may include:

  • blood pressure and heart rate;
  • weight, BMI or waist circumference;
  • pulses and other signs of vascular disease;
  • the penis for curvature, plaques, foreskin or other structural changes;
  • the testes for size, position or a mass;
  • body-hair pattern, breast tissue or other features relevant to hormone status; and
  • a basic neurological assessment when symptoms suggest it.

A rectal or prostate examination is not required simply because a man has ED. It may be appropriate if there are urinary symptoms, prostate concerns or another specific indication. The clinician should explain what is proposed and obtain consent.

Which blood tests are used for ED?

Glucose or HbA1c

An HbA1c test estimates average glucose over the preceding two to three months. A fasting glucose is an alternative in some settings. These tests can identify previously unrecognised diabetes or assess control in a man who already has it.

Lipid profile

A lipid profile measures cholesterol fractions and triglycerides. It contributes to cardiovascular risk assessment rather than diagnosing the penile problem directly.

Testosterone

The EAU basic work-up includes total testosterone taken early in the morning and fasting. Testosterone varies with time of day, food intake, illness and laboratory method. If it is low, repeat measurement and further endocrine assessment are normally needed before testosterone deficiency is diagnosed. Calculated free testosterone may help in selected cases, particularly where sex hormone-binding globulin is likely to make total testosterone hard to interpret.

Other blood tests

Luteinising hormone, prolactin, thyroid tests, full blood count, kidney or liver tests may be useful when symptoms, examination, medication or initial results point to a particular condition. They are not all mandatory for every man with ED. PSA testing should follow its own clinical indications and a discussion of benefits and limitations; ED alone is not a reason to order it automatically.

How is cardiovascular risk assessed?

ED shares risk factors with cardiovascular disease and can act as a risk marker. A UK assessment may include blood pressure, lipids, glucose status, smoking, family history and QRISK3 where appropriate. NICE recommends QRISK3 for eligible people aged 25 to 84 who do not already have cardiovascular disease. ED is included as a risk factor in QRISK3.

Men with known heart disease or symptoms during exertion may need a more specific assessment before sexual activity or an ED medicine is considered safe. Unstable angina, uncontrolled hypertension, severe heart failure, a recent cardiovascular event or a high-risk rhythm problem requires clinician-led management. A consumer risk calculator cannot provide clearance for sexual activity or PDE5 treatment in these situations.

When is a penile Doppler ultrasound needed?

Dynamic penile duplex Doppler ultrasound measures arterial inflow and blood retention after a medicine is used to create an erection. A specialist may consider it when:

  • vascular ED is strongly suspected and the result could change treatment;
  • oral treatment has failed despite correct use;
  • there is a history of pelvic or perineal trauma;
  • penile reconstructive or vascular surgery is being considered; or
  • the diagnosis remains uncertain in a complex case.

The test can produce misleading results if anxiety prevents a full response or if the medicine dose is inadequate. It is not a routine requirement before prescribing sildenafil or tadalafil.

What is night-time erection testing?

Nocturnal penile tumescence and rigidity testing records erections during sleep over more than one night. Preserved night-time function may support a non-organic component, while an abnormal recording may support a physical contributor. Sleep quality, depression, age and test conditions can affect results, so this is a specialist tool rather than a definitive “physical versus psychological” test.

Are injection tests or scans always necessary?

No. An intracavernosal injection test observes the erection response after a vasoactive medicine is injected into the penis. On its own it provides limited vascular information and is generally combined with Doppler ultrasound when clinically warranted. More invasive vascular studies are used rarely, usually when trauma-related arterial repair is being considered.

MRI and CT are not routine ED investigations. They may be used for another suspected condition, not to confirm ordinary ED.

When should you be referred to a specialist?

Referral may be appropriate for:

  • lifelong ED or ED beginning at a young age without a clear explanation;
  • pelvic or perineal trauma;
  • marked penile curvature, pain or another anatomical abnormality;
  • suspected complex hormone or neurological disease;
  • a significant cardiovascular safety concern;
  • persistent ED despite properly used first-line treatments;
  • adverse effects or contraindications that limit treatment choices;
  • consideration of injections, penile implant surgery or selected advanced therapies; or
  • complex psychosexual distress that needs specialist support.

Urgency depends on the finding. A testicular mass, severe neurological symptoms, suspected acute cardiovascular disease or priapism should follow the relevant urgent pathway rather than a routine ED referral.

Preparing for an ED appointment

Bring or provide an accurate list of medicines and supplements. It can help to note when symptoms began, whether erections occur in different settings, and any change in libido, ejaculation, penile shape or general health. If you use GTN, isosorbide, nicorandil, “poppers” or a medicine for pulmonary hypertension, state this clearly because it can determine whether a PDE5 inhibitor is safe.

You do not need to bring a partner. A partner can join if you want and if the service permits it. The consultation should still allow private discussion of sexual history and safety.

More common questions

Should every man with ED have a heart scan?

No. UK cardiovascular assessment normally starts with history, examination, standard risk factors and QRISK3 where applicable. Additional cardiac tests are selected according to symptoms, known disease and assessed risk.

Make the first step straightforward

Begin with the Heracles ED assessment and provide your symptoms and current medicines. Our team brings specialist sexual-health experience to a discreet online service, with further tests and consultations available.