Retrograde Urethrogram (RUG): Why It's Done, What to Expect and Results
Updated: 2 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: November 2026 · How we review
Quick Answer
A retrograde urethrogram (RUG) is an X-ray test that checks the urethra, the tube that carries urine out of the body, for narrowing, blockage or injury. A provider places a small tube at the tip of the urethra and injects contrast dye while X-rays are taken. It takes only a few minutes and may cause brief discomfort.
What the research says
RUG is the standard test for strictures, with some limits: in a study of men with urethral strictures, RUG and MRI urethrography diagnosed strictures equally well (85%), but MRI gave extra information in 35%, such as more accurate stricture length and scarring of surrounding tissue (Osman Y et al., European Urology, 2006) [2]
Ultrasound can add detail about stricture length: in 97 men with suspected anterior urethral stricture, urethral ultrasound found strictures with 86.6% sensitivity and 94.6% specificity compared with RUG, though it measured strictures as shorter than RUG did (Shahsavari R et al., Open Access Macedonian Journal of Medical Sciences, 2017) [3]
Key takeaways
An X-ray test that uses contrast to check the urethra for narrowing, blockage or injury.
Most often done in men after pelvic injury or for suspected strictures.
Takes only a few minutes; no preparation needed.
Mild burning and a little blood in the urine for about a day are normal.
Results guide treatments such as urethral dilation or urethroplasty.
What is a retrograde urethrogram?
"Retrograde" means contrast is sent backward, from the tip of the urethra toward the bladder, the opposite of the normal flow of urine. On X-ray, the contrast outlines the inside of the urethra, showing where it's narrowed, torn or leaking. It's often paired with a voiding cystourethrogram (VCUG), which shows the urethra as urine flows out. Sources: [1]
A retrograde urethrogram takes only a few minutes.
Why is it done?
The test checks the urethra for damage.
A pelvic or groin injury, such as a pelvic fracture, which can tear the urethra.
Blood at the tip of the penis or the urinary opening.
Inability to pee or a weak stream, such as from urinary retention.
A suspected urethral stricture from scar tissue.
Difficulty passing a catheter, or before placing one after an injury.
Planning or checking urethral surgery, such as urethral reconstruction. Sources: [1]
It can show strictures, blockages, tears, abnormal connections (fistulas) and pouches (diverticula). Sources: [1]
How do I prepare?
No preparation is needed. Tell your provider about allergies, especially to contrast dye or iodine, and about any medicines. Sources: [1]
What happens during the test?
You lie on your side on an X-ray table with one leg bent.
The area is cleaned with an antiseptic, and numbing gel may be applied; you wait a few minutes for it to work.
A small tube is gently placed in the opening of the urethra.
Contrast is slowly injected with a syringe while X-rays are taken.
You may be asked to pee into a container while more images are taken. Sources: [1]
The test only takes a few minutes. It shouldn't hurt, though you may feel pressure or discomfort; tell your provider if it hurts. Sources: [1]
After the test
Drinking water helps flush out the contrast.
Mild burning when you pee and a little blood in your urine are normal for about a day.
Drink plenty of water to help flush out the contrast.
Call your provider if you can't pee, if discomfort or bleeding lasts more than a day, or if you have a fever or swelling. Sources: [1]
Risks
The test is very low risk. Rarely, it can cause a urinary tract infection, an allergic reaction to the contrast or injury to the urethra or bladder. Sources: [1]
Understanding your results
In an emergency, results are available right away; otherwise, they may take a few days. A normal result means contrast flowed smoothly, so another cause should be looked for. An abnormal result may show the location and length of a stricture, a blockage or a tear. If more detail is needed, your provider may recommend a cystoscopy, ultrasound or MRI. Treatment may include stretching the urethra (dilation) or surgery (urethroplasty). Sources: [1, 2, 3]
Conclusion
A retrograde urethrogram is a quick X-ray test that gives a clear map of the urethra. It's the go-to test after pelvic injuries and for planning treatment of strictures, and side effects are usually mild and short-lived.
Keep learning: read about urethral stricture and the VCUG.
Frequently asked questions
What is a retrograde urethrogram?
An X-ray test that uses contrast to check the urethra for narrowing or injury.
Why is it done?
After pelvic injuries, for blood at the urinary opening, trouble peeing or suspected strictures.
Does it hurt?
It shouldn't hurt, though it may be uncomfortable.
How long does it take?
Only a few minutes.
Do I need to prepare?
No preparation is needed.
Is it only for men?
It's most often done in men but can be used in women.
What's normal after the test?
Mild burning and a little blood in the urine for about a day.
What are the risks?
Rarely, infection, contrast allergy or urethral injury.
What's the difference between a RUG and a VCUG?
A RUG fills the urethra from the tip; a VCUG fills the bladder and images you peeing.
What happens if a stricture is found?
Treatment may include dilation or urethroplasty.
Related Reading
Urethroplasty: Procedure, Recovery and Success Rate explains urethroplasty for urethral stricture.
Urethral Stricture: Symptoms, Causes, Diagnosis, and Treatment Explained the narrowing a RUG most often finds.
The Urethra: Anatomy, Function, and Urinary Health the tube this test examines.
Restoring Urinary Flow: A Guide to Posterior Urethral Reconstruction surgery planned with a RUG.
Voiding Cystourethrogram (VCUG): Why It's Done, What to Expect and Reflux Grades the companion X-ray of the bladder and urethra.
Hypospadias: Symptoms, Causes & Treatment Explained a urethral birth defect.
References
Cleveland Clinic. Retrograde Urethrogram: Purpose, Procedure, Risks & Results. Cleveland Clinic. Last updated August 21, 2023. https://my.clevelandclinic.org/health/diagnostics/25212-retrograde-urethrogram
Osman Y, El-Ghar MA, Mansour O, et al. Magnetic resonance urethrography in comparison to retrograde urethrography in diagnosis of male urethral strictures: is it clinically relevant? Eur Urol. 2006;50(3):587-593. PMID 16457942. https://doi.org/10.1016/j.eururo.2006.01.015
Shahsavari R, Bagheri SM, Iraji H. Comparison of diagnostic value of sonourethrography with retrograde urethrography in diagnosis of anterior urethral stricture. Open Access Maced J Med Sci. 2017;5(3):335-339. PMID 28698753. https://doi.org/10.3889/oamjms.2017.073
Medical disclaimer
This article is for general education only and does not replace advice from a qualified healthcare professional. Talk to your doctor about your own diagnosis and treatment, and seek emergency care right away for severe or sudden symptoms.
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