Transrectal Ultrasound (TRUS): Purpose, Procedure, Risks and Recovery

Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026 · How we review

Quick Answer: What is a transrectal ultrasound?

A transrectal ultrasound (TRUS) is an imaging test that uses a small, finger-sized probe placed in the rectum to send sound waves that create live pictures of the prostate. It helps check an abnormal rectal exam or high PSA, guides prostate biopsies and some treatments, takes under 30 minutes, and uses no radiation. [1][2][3]

What the research says

• A prostate biopsy through the skin causes fewer infections than one through the rectum. In 5 randomized trials with 3,072 men, a biopsy taken through the skin between the scrotum and anus (transperineal) had lower odds of infection than a transrectal biopsy (pooled odds ratio 0.38), with no difference in finding clinically significant prostate cancer (odds ratio 1.01). (Marra et al., European Urology Oncology, 2026) [6]

• Infection-related hospital stays drop by about three-quarters with the transperineal route. Across 10 randomized trials covering 4,188 biopsies, the transperineal route lowered the odds of hospitalization for infection by 77% (odds ratio 0.23) and the odds of fever after the biopsy (odds ratio 0.68). (Stangl et al., European Urology Focus, 2026) [7]

• Antibiotics chosen from a rectal swab halve urinary infections after a TRUS biopsy. In 9 randomized trials with 3,002 men, fever-causing urinary tract infections occurred in 2.7% of men given swab-targeted antibiotics versus 5.2% given standard antibiotics (risk ratio 0.54); sepsis rates did not differ significantly (1.3% vs 1.8%). (Tsuboi et al., European Urology Open Science, 2025) [8]

Key takeaways

• A transrectal ultrasound uses sound waves, not radiation, to create real-time images of the prostate. [1][3]

• Doctors use TRUS to look into an abnormal digital rectal exam, a high PSA result, urinary symptoms or infertility. [1]

• The scan itself usually takes less than 30 minutes, and most people go home the same day. [1]

• The ultrasound alone has no known risks; side effects such as blood in the urine or semen come from a biopsy done during the scan. [1]

• Fever, blood clots in the urine or trouble urinating after a biopsy are reasons to call your doctor. [1]

Transrectal ultrasound at a glance

Feature	Details
What it is	An ultrasound scan done with a probe placed in the rectum [1]
Other names	Endorectal ultrasound (ERUS), prostate sonogram, prostate ultrasound [1]
Main organ imaged	Prostate; sometimes pelvic and reproductive organs in women [1]
Radiation	None [1][3]
Typical length	Under 30 minutes [1]
Can include a biopsy?	Yes; the images guide a thin needle to take prostate tissue samples [1][2]
Going home	Usually the same day [1]

What is a transrectal ultrasound?

A transrectal ultrasound is an imaging test that places a small ultrasound probe inside the rectum to take pictures of the prostate. [1] The prostate sits just in front of the rectum, so a probe in the rectum can get a close, clear view of the gland. [2][3]

The probe sends out sound waves. These waves bounce off the prostate and nearby tissue, and a computer turns the echoes into live images on a screen. [1][3]

Doctors also call the test an endorectal ultrasound (ERUS), a prostate sonogram or a prostate ultrasound. [1] In women, a transrectal ultrasound is sometimes used to look at the pelvic and reproductive organs. [1]

Want to understand the gland itself first? Read our guide to where the prostate is and what it does.

Why would a doctor order a transrectal ultrasound?

A doctor usually orders a transrectal ultrasound to get a closer look at the prostate after a test result or symptom raises a question. [1] Common reasons include:

• An abnormal digital rectal exam, where the doctor feels a lump or change in the prostate [1]

• A high level of prostate-specific antigen (PSA) in a blood test [1]

• Prostate symptoms, such as trouble urinating [1]

• A prostate condition that needs treatment [1]

• Infertility [1]

What conditions can a transrectal ultrasound help find?

A transrectal ultrasound helps doctors diagnose several prostate and nearby conditions. [1] For some of them, the scan is paired with a needle biopsy.

Condition	How TRUS helps
Benign prostatic hyperplasia (BPH)	Shows an enlarged prostate [1]
Prostatitis	Helps check for inflammation of the prostate [1]
Prostate cancer	Guides a needle biopsy to take tissue samples for testing [1][2]
Cysts in the reproductive organs	Shows fluid-filled sacs [1]
Some rectal and anal cancers	Helps doctors assess the area, often with a biopsy [1]

Which treatments use transrectal ultrasound?

Transrectal ultrasound also guides treatments, because live images show doctors exactly where to work inside the prostate. [1] It is used during:

• Brachytherapy, which places small radioactive seeds in the prostate to treat cancer [1]

• Cryosurgery, which freezes prostate cancer cells [1]

• High-intensity focused ultrasound (HIFU), which uses focused heat to treat prostate cancer [1]

• Draining an abscess, a pocket of pus [1]

Cryosurgery and HIFU are both forms of focal therapy for prostate cancer.

How do you prepare for a transrectal ultrasound?

Preparing for a transrectal ultrasound mainly means sharing your health history, adjusting some medicines and emptying your bowel and bladder. [1]

Tell your provider if you:

• Have any medication allergies [1]

• Have a heart or lung condition [1]

• Usually take antibiotics before surgery [1]

Your provider may ask you to:

• Stop aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, for a time [1]

• Stop blood thinners for a time [1]

• Use an enema 1 to 4 hours before the test to clear the rectum [1]

• Urinate right before the procedure [1]

If you will have a biopsy, your provider may also give you antibiotics to lower the risk of infection. [1][4]

What happens during a transrectal ultrasound?

During a transrectal ultrasound, you lie on your side while a lubricated probe is gently placed in your rectum to take images. [1] Here is what to expect, step by step:

1. Positioning. You lie on your side with your knees bent toward your chest. [1]

2. Inserting the probe. The provider places a lubricated probe, about the size of a finger, into your rectum. [1] You may feel pressure, similar to needing a bowel movement. [1]

3. Taking images. The probe sends sound waves to the prostate, and live images appear on a screen. [1][3]

4. Finishing up. The scan usually takes less than 30 minutes. [1]

What happens during a TRUS-guided prostate biopsy?

A TRUS-guided prostate biopsy uses the ultrasound images to steer a thin, hollow needle into the prostate to collect tissue samples. [1][2]

• The provider first numbs the prostate. [1]

• The needle passes through the wall of the rectum into the prostate. [1]

• The provider collects several small tissue samples. [1]

• The samples go to a lab, where they are checked for cancer or other problems. [1]

The skill of the person doing the biopsy matters. One study found that biopsies done by more experienced operators were more likely to find cancer in men with lower PSA levels. [5]

Is a transrectal ultrasound safe?

A transrectal ultrasound on its own is safe and has no known risks. [1] It is minimally invasive, uses no radiation and shows soft tissue in real time. [1]

Benefit	Why it matters
Minimally invasive	No cuts are needed for the scan itself [1]
No radiation	Uses sound waves instead of X-rays [1][3]
Real-time images	Lets doctors guide needles and treatments as they work [1]
Clear soft-tissue view	Shows the prostate in detail [1]

What are the side effects of a TRUS-guided biopsy?

The side effects of a TRUS-guided biopsy come from the needle, not the ultrasound, and they are usually temporary. [1] Possible effects include:

• Blood in the semen [1]

• Blood in the urine [1]

• Rectal bleeding [1]

• Pain or painful urination [1]

• Trouble urinating (urinary retention) [1]

• Infection [1]

• Erectile dysfunction [1]

What is recovery like after a transrectal ultrasound?

Recovery after a transrectal ultrasound is usually short, and most people go home the same day. [1] Ask your provider ahead of time whether you will need someone to drive you home. [1]

What to expect	Ultrasound only	Ultrasound with biopsy
Going home	Same day [1]	Same day [1]
Normal activities	Usually right away [1]	You may need to wait a few days [1]
Full recovery	Quick [1]	A few weeks or more [1]
Diet	Your regular diet [1]	Your regular diet [1]
Medicines	Follow your provider's advice	Avoid aspirin and NSAIDs for at least 3 days; take any prescribed antibiotics [1]
Fluids	Follow your provider's advice	Drink 6 to 8 glasses of water a day for at least 3 days [1]

A warm bath may ease rectal soreness. [1]

When will you get your transrectal ultrasound results?

Transrectal ultrasound biopsy results come from a lab, and your provider will contact you when they are ready. [1] Ask your care team when to expect the call and what the next steps could be.

If the results show prostate cancer, your doctor will explain your options. Our guides to metastatic prostate cancer and focal therapy can help you prepare questions.

When should you call a doctor after a transrectal ultrasound?

Call your doctor after a transrectal ultrasound or biopsy if you notice any of these warning signs: [1]

• Blood clots in your urine

• Bloody urine that doesn't go away

• Fever

• Trouble urinating that doesn't get better

• Pain that medicine doesn't relieve

Don't wait for your follow-up visit if any of these happen. A fever with chills or shaking after a biopsy can signal a serious infection (sepsis) and needs urgent care the same day.

Conclusion

A transrectal ultrasound is a quick, radiation-free way to see the prostate up close. [1] It helps doctors check abnormal exam or PSA results, guide biopsies and deliver some prostate treatments. [1] The scan itself has no known risks, and most side effects come from a biopsy and fade with time. [1] Knowing how to prepare, what to expect and which warning signs need a call makes the day easier.

Have a TRUS coming up? Save this guide, write down your questions for your care team and explore more plain-language guides in our Diseases & Conditions library. Start with our prostate health guide to understand the gland your scan will look at.

FAQ

What is a transrectal ultrasound used for?

A transrectal ultrasound is used to take close-up images of the prostate and to guide prostate biopsies. Doctors order it after an abnormal rectal exam, a high PSA result, urinary symptoms or infertility, and use it to guide some prostate cancer treatments. [1]

Does a transrectal ultrasound hurt?

A transrectal ultrasound usually causes pressure rather than pain, similar to needing a bowel movement. If a biopsy is done, the provider numbs the prostate first, though some soreness afterward is possible. [1]

How long does a transrectal ultrasound take?

A transrectal ultrasound usually takes less than 30 minutes. Most people go home the same day. [1]

How do I prepare for a transrectal ultrasound?

Preparation for a transrectal ultrasound often includes an enema 1 to 4 hours before and emptying your bladder right before the test. Your provider may also ask you to stop aspirin, NSAIDs or blood thinners and to share any allergies or heart or lung conditions. [1]

Is a transrectal ultrasound safe?

A transrectal ultrasound on its own has no known risks and uses no radiation. Side effects such as bleeding or infection are linked to a biopsy done during the scan. [1]

What are the side effects of a TRUS biopsy?

The side effects of a TRUS biopsy can include blood in the semen or urine, rectal bleeding, painful urination, trouble urinating, infection and erectile dysfunction. These effects are usually temporary. [1]

How long does recovery take after a TRUS biopsy?

Recovery after a TRUS biopsy may require a few days before normal activities, and full recovery can take a few weeks or more. Without a biopsy, most people return to normal activities right away. [1]

When should I call a doctor after a transrectal ultrasound?

Call a doctor after a transrectal ultrasound if you have blood clots in your urine, bloody urine that doesn't go away, fever, trouble urinating that doesn't improve or pain that medicine doesn't relieve. [1]

Do I need antibiotics before a TRUS biopsy?

Yes. Antibiotics are usually given before a TRUS-guided biopsy to lower the risk of infection. Take them exactly as instructed, and call your doctor right away if you get a fever or chills afterward.

Is blood in semen normal after a prostate biopsy?

Yes. Blood in the semen is common after a TRUS biopsy and can last for several weeks. Call your doctor if you have heavy bleeding in your urine or stool or cannot urinate.

Related Reading

PSA Test: Normal Levels by Age, How to Prepare and What High Results Mean explains the blood test that often leads to a transrectal ultrasound.

MRI-Guided Prostate Biopsy: Fusion Biopsy, Prep, Risks and Results describes using MRI to target suspicious areas of the prostate.

Active Surveillance for Prostate Cancer: Tests, Benefits and Risks covers monitoring low-risk prostate cancer instead of treating right away.

Benign Prostatic Hyperplasia (BPH): Symptoms, Causes, and Treatment explains an enlarged prostate and how it is treated.

References

1. Cleveland Clinic. Transrectal Ultrasound. Cleveland Clinic. Last updated August 25, 2022. https://my.clevelandclinic.org/health/treatments/24518-transrectal-ultrasound

2. Canadian Cancer Society. Transrectal ultrasound (TRUS). Canadian Cancer Society. Last updated January 2025. https://cancer.ca/en/treatments/tests-and-procedures/transrectal-ultrasound-trus

3. Radiological Society of North America and American College of Radiology. Ultrasound - Prostate. RadiologyInfo.org. Last updated August 1, 2026. https://www.radiologyinfo.org/en/info/us-prostate

4. Morin A, Bergevin M, Rivest N, et al. Antibiotic prophylaxis for transrectal ultrasound-guided prostate needle biopsy: Compared efficacy of ciprofloxacin vs. the ciprofloxacin/fosfomycin tromethamine combination. Can Urol Assoc J. 2020;14(8):267-272. PMID 32209218. https://doi.org/10.5489/cuaj.6248

5. Tadtayev S, Hussein A, Carpenter L, et al. The association of level of practical experience in transrectal ultrasonography guided prostate biopsy with its diagnostic outcome. Ann R Coll Surg Engl. 2017;99(3):218-223. PMID 27659356. https://doi.org/10.1308/rcsann.2016.0308

6. Marra G, Bazzurro F, Dematteis A, et al. Transperineal Versus Transrectal Biopsy for Prostate Cancer Diagnosis: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Eur Urol Oncol. 2026. Epub ahead of print. PMID 41667335. https://doi.org/10.1016/j.euo.2026.01.009

7. Stangl FP, Day E, Vallée M, et al. Infectious Complications After Transrectal Versus Transperineal Prostate Biopsy: A Systematic Review and Meta-analysis. Eur Urol Focus. 2026;12(2):275-283. PMID 40774844. https://doi.org/10.1016/j.euf.2025.07.005

8. Tsuboi I, Kardoust Parizi M, Matsukawa A, et al. Rectal Swab-based Targeted Prophylactic Antibiotics Reduce Infectious Complications After Transrectal Prostate Biopsy: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Eur Urol Open Sci. 2025;80:57-65. PMID 41064532. https://doi.org/10.1016/j.euros.2025.08.007

Medical disclaimer

This article is for general education and does not replace advice from your own doctor. Always talk with a qualified healthcare professional about your symptoms, test results and treatment choices. If you think you have a medical emergency, contact your local emergency services right away.