Ultrasound scan
A scan that uses high-frequency sound waves (no X-rays) to make live pictures of organs, blood flow, muscles or a developing baby to help diagnose a problem.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- An ultrasound uses sound waves to make live pictures of organs, blood flow, muscles or a baby, and uses no X-rays or radiation.
- It is operator-dependent and cannot see well through gas or bone, so a normal scan does not rule out every condition and another test is sometimes needed.
- There is usually no recovery — most people go straight back to normal activities; some results are discussed at the time, with a full report often within days to a couple of weeks.
- Some scans need preparation, such as a full bladder or not eating for a few hours; the team will tell you what is needed.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your radiologist will give you advice for your situation.
Gives live, moving pictures of organs, blood flow, muscles and a developing baby
When the question needs detail ultrasound cannot provide — for example assessing bone, the lungs, or structures hidden behind gas or deep in larger...
You lie on a couch while a probe is moved over the skin (or, for internal scans, gently inside). It is usually usually not painful and you can ask...
A clear route to your written report and a named person to explain it.
You lie on a couch while a probe is moved over the skin (or, for internal scans, gently inside). It is usually...
You wipe off the gel, empty your bladder if it was full, and can eat, drink, drive and return to work immediately.
Sometimes the sonographer or radiologist gives an idea of the findings at the time; a full written report is often...
The report reaches the doctor who referred you, who explains the results and any next steps (sooner if urgent).
What is an ultrasound scan?
An ultrasound scan uses high-frequency sound waves to create live, moving pictures of the inside of your body. It does not use X-rays or radiation. It is widely used to look at organs in the tummy and pelvis, the thyroid, blood vessels, muscles and tendons, and to monitor pregnancy.
A doctor usually requests an ultrasound to investigate a symptom or check a known problem. A trained sonographer or a radiologist moves a small handheld probe over the skin (or, for some scans, uses an internal probe) and watches the images on a screen, taking measurements and still pictures.
Ultrasound is safe and repeatable, but it has limits: sound waves do not pass well through gas or bone, and image quality depends on the operator's skill and the part of the body. A normal scan does not rule out every illness, and ultrasound may pick up harmless 'incidental' findings or need to be followed by another test.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
External (transabdominal/surface) ultrasound
A probe is moved over the skin with gel, used for the tummy, pelvis, thyroid, blood vessels, muscles and pregnancy. Usually not painful and the most common type.
Internal ultrasound (transvaginal or transrectal)
A slim probe with a protective cover is gently placed inside the vagina or back passage to see the pelvic organs or prostate more closely. May feel a little uncomfortable but...
Doppler / vascular ultrasound
Measures blood flow through arteries and veins, used to check for clots, narrowing or circulation problems.
Musculoskeletal ultrasound
Looks at muscles, tendons, ligaments and joints in real time, and can guide injections to the right spot.
Preparing for your scan
- Follow any bladder instructions — some pelvic and pregnancy scans need a full bladder, so you may be asked to drink water and not wee beforehand.
- Follow any fasting instructions — scans of the gallbladder, liver or upper tummy often need you not to eat for several hours.
- Wear loose, comfortable clothing that gives easy access to the area being scanned.
- For an internal scan, you can ask questions about what is involved and request a chaperone; it is done only with your consent.
- Take your usual medicines unless told otherwise.
- Allow time for the appointment and ask how and when you will get your results.
- Tell the team if you have a latex allergy, as probe covers may need to be changed.
What happens
For an external scan, you lie on a couch and the sonographer puts a slippery gel on your skin, then moves a small handheld probe over the area while watching the pictures on a screen. The room is often dimmed to see the images clearly. You may be asked to change position, breathe in, or hold your breath briefly. It is usually not painful, though the gel can feel cold.
For an internal scan, a slim probe with a protective cover and gel is gently passed into the vagina or back passage to get a closer view of the pelvic organs or prostate. This may feel a little uncomfortable but should not be painful, and is done with your consent and the option of a chaperone.
Most scans take about 10–45 minutes. Afterwards you wipe off the gel and can carry on as normal straight away. Sometimes the sonographer or radiologist can give an idea of the findings at the time, but a full written report is often sent to your doctor afterwards.
Is this scan right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- When the question needs detail ultrasound cannot provide — for example assessing bone, the lungs, or structures hidden behind gas or deep in larger patients.
- As a stand-alone 'all clear' for cancer or serious disease, because it cannot see everything.
- Asymptomatic people seeking reassurance scans without a clear question, where incidental findings may cause harm.
- When a faster or more definitive test (CT, MRI or endoscopy) is the right first choice for the symptom.
Delay or rearrange if…
- Bladder or fasting preparation has not been followed, as the scan may be inadequate.
- There is an active infection or skin problem at the scan site that should be treated first.
- You are not comfortable proceeding with an internal scan and want more information or a chaperone.
- Key prior results are missing that would change which test is needed.
- An urgent symptom needs same-day assessment rather than a booked scan.
Alternatives to discuss
- No scan, or watchful waiting, if symptoms are mild and a scan would not change management.
- CT scan for bone, lung, or when gas or body shape limits ultrasound.
- MRI for detailed soft-tissue, brain or spine questions.
- Blood tests or other simple tests that may answer the question first.
- Going through an NHS pathway rather than self-funding, where time allows.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Gives live, moving pictures of organs, blood flow, muscles and a developing baby
- Uses no X-rays or radiation, so it is safe to repeat and is widely used in pregnancy
- Quick, widely available, and usually needs no injection or preparation beyond simple instructions
- Can guide procedures such as injections, drainage or biopsies to the right place
- Can help diagnose a problem, monitor a known condition, or provide reassurance
Risks & complications
- Cold or slightly messy gel, and mild discomfort from probe pressure
- Some discomfort or embarrassment with an internal (transvaginal or transrectal) scan
- A full-bladder scan can be uncomfortable while you wait
- An 'incidental' finding picked up by chance that may be harmless but leads to more tests and worry
- A scan that cannot answer the question because gas, bowel, bone or body shape blocks the view
- A normal scan that gives false reassurance when a problem is present but not seen
- Needing a different or repeat test (for example CT, MRI or blood tests) to get the answer
- Findings that differ between operators because ultrasound depends on the person doing it
- Very minor discomfort or, rarely, light spotting after an internal scan
- A missed or under-estimated problem because of the test's limits
- An incidental finding that triggers an invasive follow-up test which itself carries small risks
Ultrasound is one of the safest scans and uses no radiation, so the main issues are its limits rather than direct harm: it depends on the operator's skill and cannot see well through gas or bone. A normal scan does not rule everything out. Ask what the scan can and cannot show for your particular question, and what happens if it is unclear.
Published figures to discuss
Ultrasound uses no radiation and direct harm is very rare, so meaningful 'rates' relate mainly to its accuracy and limits rather than complications. How well it performs depends heavily on the operator's skill, the body part, and patient factors such as body shape and bowel gas. False reassurance, missed findings and incidental findings are the main considerations, and these vary too much by indication to give a single reliable figure.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Radiation exposure | None | Diagnostic ultrasound uses sound waves rather than ionising radiation. | Guide sourcesClinical context |
| Limited views | Common with bowel gas, body habitus, pain, wounds or deep structures | A limited scan may need repeat ultrasound, CT, MRI or specialist review. | NHS — Ultrasound scannhs.ukSource-linked context |
| Incidental finding | Common | Simple cysts, benign nodules and anatomical variants are often found and may or may not need follow-up. | Guide sourcesClinical context |
| False reassurance from a normal ultrasound | Possible | Ultrasound is excellent for many questions but cannot exclude every cause of symptoms. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is usually no physical recovery from an ultrasound. Most people return to normal activities, work and driving straight away. The main thing you may be waiting for is the written report, although some findings are shared at the time.
- No after-effects at all for most people
- Relief at emptying a full bladder after a pelvic or pregnancy scan
- Very mild, brief discomfort after an internal scan
- A short wait for the written report, which can feel anxious
Aftercare
- Carry on with normal activities, work and driving — no recovery is usually needed.
- Empty your bladder after a full-bladder scan and drink normally.
- If you had an internal scan and notice mild spotting, this usually settles quickly; seek advice if it is heavy or persistent.
- Make a note of what you were told at the time and when the full report will be ready.
- Chase the result if you have not heard within the expected time — do not assume no news is good news.
- Ask for a copy of the report and images if you may need them for another opinion.
- If symptoms continue despite a normal scan, go back to your doctor, as ultrasound does not see everything.
- Bladder or fasting instructions followed as advised
- Comfortable clothing with easy access to the area
- Questions ready about what the scan can and cannot show
- A chaperone requested if you would like one for an internal scan
- Date and route for getting your full results
- A named contact if you have questions after the scan
⚠ Get urgent help if…
- Heavy or persistent vaginal bleeding after an internal scan
- Severe or worsening pelvic or tummy pain after the scan
- Signs of infection such as fever, chills or offensive discharge after an internal scan
- Fainting or feeling very unwell during or after the appointment
- New or rapidly worsening symptoms while you wait for results — seek advice rather than waiting for the report
- Symptoms that continue or get worse despite a normal scan result
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your radiologist gives you.
Results & realistic expectations
A good result is a clear scan that answers the question your doctor asked — reassurance that nothing concerning is seen, an explanation for your symptoms, or measurements that guide care. Some findings can be shared at the time, but a full written report from a radiologist or sonographer often follows within days to a couple of weeks.
Because ultrasound depends on the operator and cannot see through gas or bone, a normal scan does not prove you are free of disease. If your symptoms persist, tell your doctor — a further test such as CT, MRI or blood tests may be needed. The scan alone cannot tell you what a finding means for you; that needs your doctor to interpret it with your symptoms and other results.
An ultrasound is a snapshot in time and can become out of date if your symptoms change or time passes. Because it is safe and uses no radiation, it can be repeated when useful — for example to monitor a cyst, a pregnancy or a blood vessel over time. Your doctor will advise whether and when a repeat scan is helpful.
Related tests, treatments or support
Ultrasound is often a first-line test and is commonly combined with blood tests; depending on the findings it may be followed by a CT, MRI, mammogram or biopsy. In pregnancy and gynaecology it is the main imaging method. Your doctor should explain how the pieces fit together rather than ordering tests in isolation.
Follow-up & long-term care
Some results are discussed at the appointment, but a full written report usually goes to the doctor who referred you, who explains it and arranges any next steps — reassurance, treatment, a further test, or a specialist referral. Make sure you know who is responsible for giving you the result and by when, and chase it if you have not heard.
Repeat, follow-on and what comes next
- A scan that cannot answer the question may need to be repeated by a more experienced operator or replaced by CT or MRI.
- An unclear or borderline finding may need a follow-up scan after an interval to see if it changes.
- A finding may lead to a further targeted test or a biopsy to find out what it is.
- Comparing with previous scans often matters — bring or request prior imaging where possible.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear route to your written report and a named person to explain it.
- A plan for any incidental or unclear findings, with sensible thresholds for further tests.
- Advice to return if symptoms persist despite a normal scan.
- Your images and report made available to you and any other clinician you choose.
- Honest advice on whether and when any repeat scan is actually needed.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The area scanned and the number of regions
- Whether it is a more specialist scan (for example detailed vascular Doppler or musculoskeletal)
- Whether a consultant radiologist performs or reports it
- Same-day reporting versus a standard turnaround
- Whether the scan guides a procedure such as an injection or biopsy
- Any follow-up consultation to explain the results
- Whether further tests are needed if something is found
- The sonographer/facility fee and which area(s) are included
- Whether a written report from a radiologist is included
- The expected turnaround time for results
- Whether a consultation to explain results is included
- What happens (and what it costs) if the scan is inconclusive or needs repeating
- What happens if an incidental finding needs further tests
- The cancellation and rebooking policy
On the NHS? Ultrasound is commonly available on the NHS when a doctor decides it is clinically needed, including routine pregnancy scans; private scans are mainly used for speed, choice or extra reassurance, and a referral is normally still required.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not explaining that a normal scan does not rule out every condition.
- Performing an internal scan without clear consent or the option of a chaperone.
- Not discussing incidental findings and how they will be handled.
- Over-stating what the scan can show, given that it depends on the operator.
- No clear plan for who gives the result and by when.
Marketing red flags
- Reassurance 'screening' scans sold to well people without a clear clinical question.
- Claims that an ultrasound can rule out cancer or guarantee everything is normal.
- Souvenir or non-diagnostic scans presented as a medical check.
- Adding extra scans without a clear reason.
- No named clinician to report the scan or explain results.
Choosing a specialist safely
- Check the radiologist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the radiologist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good radiologist will welcome every one of these.
- What specific question is this scan meant to answer for me?
- Will it be an external or internal scan, and what does it involve?
- What can this scan not show, and might I need another test as well?
- What happens if the scan is normal, abnormal, or unclear?
- Will I be told anything at the time, and who sends me the full report?
- If something is found by chance, how will we decide whether it needs action?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the radiologist who carries out my scan, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this scan not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Can I have an ultrasound on the NHS?
Is an ultrasound safe and does it use radiation?
Does it hurt?
Do I need to prepare?
Will I get my results straight away?
What if the scan is normal but I still feel unwell?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHS — Ultrasound scan NHS — Pregnancy ultrasound scans Royal College of Radiologists — ultrasound standards and guidance Society and College of Radiographers — ultrasound information NICE — guidance and topics on imaging
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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