Transrectal prostate biopsy

A test that takes small samples of the prostate with a thin needle passed through the wall of the rectum, guided by ultrasound and sometimes an MRI map, to look for prostate cancer.

Also called TRUS biopsy, TRUS-guided prostate biopsy, Transrectal ultrasound biopsy, Transrectal ultrasound-guided biopsy, Prostate biopsy, Prostate needle biopsy, 12-core biopsy, Biopsy through the rectum

Where: Clinic exam room
Anesthesia: Local numbing (a nerve block given through the probe), sometimes with light sedation
Time in the room: About 15 to 30 minutes
Hospital stay: Same day
Back to normal: 1 to 2 days
Back to work: Same day or next day

See the steps

ProstateRectumBladderUrethra

Where it happens. The highlighted part is what this procedure treats.

Overview

For decades, the transrectal biopsy has been the most common way to sample the prostate. An ultrasound probe is placed in the rectum, and a thin spring-loaded needle passes through the rectal wall into the prostate, which sits right in front of it. It is quick, done in the office, and the numbing medicine makes it tolerable for most men.

The rectum normally contains bacteria, and the needle carries a few of them into the prostate. That is why antibiotics are given and why infection is the main risk. Some practices first swab the rectum to check for bacteria resistant to the usual antibiotic, so the right one can be chosen.

If you had an MRI showing a suspicious area, the same fusion software used for other biopsies can guide the needle to it. Most men also have about 12 samples taken across the whole prostate.

Many centers are moving to the transperineal route, through the skin between the scrotum and anus, because it has a lower infection risk. Both routes find cancer at similar rates. U.S. guidelines allow either; European guidelines prefer the transperineal route.

The parts of your body involved

The prostate is a walnut-sized gland under the bladder. Its back surface lies against the front wall of the rectum, separated only by a thin layer of tissue. That is why a probe in the rectum gives clear pictures, and why a short needle can reach the prostate through the rectal wall.

Prostate
The gland being sampled. Most cancers start in its back and outer part, close to the rectum.
Rectum
The last part of the bowel. The ultrasound probe sits here, and the needle passes through its wall.
Urethra
The tube carrying urine through the prostate. The needle avoids it, but a little blood in the urine is common afterward.
Seminal vesicles
Small glands behind the prostate that make semen. Bleeding into them is why semen looks bloody for weeks after a biopsy.

Why it’s done

A biopsy is recommended when your PSA, MRI or exam suggests a cancer that matters may be present, or to recheck a known low-risk cancer.

A raised or rising PSA
A high or rising PSA can come from cancer, an enlarged prostate or inflammation. Only a biopsy confirms cancer.
A suspicious MRI
A PI-RADS score of 4 or 5 means a significant cancer is likely. A score of 3 is in between and is weighed with other information.
An abnormal exam
A hard area or lump felt on the finger exam.
Active surveillance
Men watching a low-risk cancer have repeat biopsies to make sure it has not changed.
Quick and widely available
It can be done in most urology offices in under half an hour with local numbing.

Other options

Transperineal biopsy
The needle goes through the skin between the scrotum and anus instead of the rectum. Infection is much less likely, and many centers need no antibiotics.
MRI first, then decide
Guidelines support a prostate MRI before a first biopsy when available. A normal MRI with a low PSA density may mean the biopsy can wait.
Repeat PSA or marker tests
Repeating the PSA, or adding blood or urine marker tests, can help decide whether a biopsy is needed now.

Getting ready

Tick items off as you go. Your checklist is saved on this device only.

1 to 2 weeks before

MRI

Many men have a prostate MRI first so suspicious areas can be targeted.

Blood thinners

Tell your team about any blood thinner. Low-dose aspirin is often continued; others such as clopidogrel, warfarin or apixaban may be paused for a few days. Never stop one on your own.

Infection risk check

Tell your team if you have taken antibiotics in the last 6 months, been in the hospital recently, traveled abroad, or had a prostate or urine infection before. These raise the chance of resistant bacteria. Some practices take a rectal swab to choose the best antibiotic.

Allergies

Tell your team about allergies to antibiotics, numbing medicines or latex.

The day before

Antibiotics

You will be told exactly when to take your antibiotic, often 30 to 60 minutes before the biopsy, and sometimes for a day afterward. Take every dose as directed.

Plan your ride

If you will have sedation, arrange for someone to drive you home.

The morning of

Enema

Many practices ask you to use a small over-the-counter enema 1 to 2 hours before the biopsy to empty the rectum.

Eat lightly

A light breakfast is usually fine if you are having only local numbing.

Medicines

Take your usual medicines unless told otherwise, except any blood thinner you were asked to pause.

The procedure, step by step

Press play or pick a step. Each drawing shows what your surgeon is doing at that moment. Your team may do some steps differently.

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1. Position and a finger exam

Most often you lie on your left side with your knees pulled up toward your chest. Some clinics use a position on your back with your legs supported. Your urologist first does a gentle finger exam of the prostate through the rectum.

More detail

The finger exam lets your urologist feel the size and any firm areas of the prostate and check that the rectum is ready for the probe.

Most often you lie on your left side with your knees pulled up toward your chest. Some clinics use a position on your back with your legs supported. Your urologist first does a gentle finger exam of the prostate through the rectum.
More detail
The finger exam lets your urologist feel the size and any firm areas of the prostate and check that the rectum is ready for the probe.
A lubricated probe about as wide as a thumb is placed into the rectum. You will feel pressure and fullness, as if you need to have a bowel movement. The probe shows live pictures of the prostate on a screen.
More detail
The probe has a channel along its side that guides the needle, so every needle pass lines up with the picture on the screen.
Through the guide channel, a thin needle places numbing medicine next to the prostate on each side, where its nerves enter. You may feel a few brief stings. After a few minutes, most men feel pressure more than pain.
More detail
This is a periprostatic nerve block, usually with lidocaine. It clearly lowers pain during the biopsy and is recommended for transrectal biopsies done awake.
Your urologist scans the prostate from top to bottom and measures its size. The size, together with your PSA, gives a number called PSA density that helps judge your risk.
If you had an MRI with a suspicious area, software fuses it with the live ultrasound so the target shows as a colored outline on the screen. Your urologist can then aim right at it.
More detail
Without fusion software, some urologists study the MRI and aim by eye, called cognitive fusion. Targeted samples find more significant cancers than random samples alone.
The spring-loaded needle passes through the rectal wall into the prostate and fires with a loud click. Each sample takes less than a second. Targeted samples, usually 2 to 5 per area, are taken from any MRI target.
More detail
Each core is about 1 to 2 centimeters long and thinner than a pencil lead. It goes into its own labeled container so the pathologist can report where any cancer was found.
About 12 samples are taken in a set pattern across both sides of the prostate, in addition to any targeted ones. Then the probe is removed. A little bleeding from the rectum is common and usually stops on its own.
More detail
If rectal bleeding continues at the end, your urologist may hold gentle pressure for a few minutes with the probe or a finger.

After the procedure

Right afterward

A short rest
You rest for a few minutes, or longer after sedation, until you feel steady.
Going home
Most men drive themselves home after local numbing alone. After sedation, someone must drive you.
Finish the antibiotics
Take any remaining antibiotic doses exactly as prescribed.

At home

Watch for fever
Check your temperature if you feel unwell, especially in the first 3 days. Fever or chills after this biopsy need urgent care.
Blood in the urine
Pink urine is common for a few days and can come and go for up to 2 weeks. Drink extra fluids for a day or two.
Blood in the stool
A little blood on the toilet paper or in the first few stools is common for 1 to 2 days.
Blood in the semen
Semen may look red or brown for 4 to 6 weeks or longer. It is harmless to you and a partner.
Discomfort
A dull ache in the rectum or between the legs for a day or two is common. Acetaminophen (Tylenol) usually helps.
Activity
Avoid heavy lifting, bicycle riding and hard exercise for about 2 to 3 days.
Sex
You can resume sex when comfortable, usually after a few days. Expect blood in the semen.
Blood thinners
Restart any paused blood thinner when your team says to, often within 1 to 2 days.

Recovery timeline

Day 0
Biopsy day
The biopsy takes about 15 to 30 minutes. You go home with some soreness and blood in the urine.
Days 1 to 3
The watch period
This is when infection, if it happens, usually shows up. Most men feel nearly normal.
Days 5 to 10
Results
The pathology report is usually ready, and your urologist goes over it with you.
Week 2
Urine clear
Blood in the urine has usually stopped.
Weeks 4 to 6
Semen clears
Blood in the semen usually fades by now, though it can last longer.
After results
Next steps
Depending on the result, the plan may be PSA checks, active surveillance, staging scans, or a talk about treatment.

What it feels like

Most men find a transrectal biopsy uncomfortable and awkward more than painful. The days after are usually easy, with the main job being to watch for fever.

Before the biopsy
Worry about pain, embarrassment about the rectal probe, and fear of the result.
What helpsAsk your urologist to explain each step. Ask about sedation if you are very anxious. Use the enema as instructed so you do not worry about the bowel.
The probe and the numbing
A feeling of fullness and pressure in the rectum, then a few short stings as the numbing goes in.
What helpsSlow, deep breaths and relaxing your buttocks make the probe more comfortable.
The clicks
A loud snap with each sample and a quick pinch or deep thud. Many men flinch at the first one.
What helpsAsk the team to count down before each sample and tell you how many are left.
The first day or two
Mild soreness, pink urine, and maybe a little blood with a bowel movement. Some men feel tired or shaky.
What helpsDrink fluids, rest, and keep a thermometer handy. Call right away for fever or chills.
Waiting for results
The wait for results can feel longer than the biopsy itself.
What helpsBook the results visit before you leave and bring someone along to it.

How well it works

The pathology report tells whether cancer is present, how aggressive it looks, and how much there is. Your urologist combines this with your PSA and MRI to plan next steps.

Grade group (Gleason score)
Graded from 1 (least aggressive) to 5 (most aggressive). Grade group 1 cancers are usually watched rather than treated.
How much cancer
The report lists how many cores contain cancer and how much of each core is involved.
Matching the MRI
If targeted cores do not explain a suspicious MRI area, a repeat biopsy or closer follow-up may be advised.
Benign or uncertain findings
Many biopsies show no cancer, or show inflammation or unusual cells. The next step may be PSA checks, a repeat MRI, or another biopsy.

Risks

Every operation has risks. These are the ones people ask about most, with honest odds where good numbers exist. Your surgeon’s own results matter more than averages.

Common

Blood in the urineCommon

Usually mild and gone within 2 weeks.

Blood in the semenCommon

Common for 4 to 6 weeks or longer. Harmless.

Rectal bleedingCommon

A small amount of blood with bowel movements for a day or two.

Soreness

A dull ache in the rectum or between the legs for a day or two.

Less common

Urine or prostate infection with feverAbout 1 to 3 in 100

Bacteria carried by the needle can cause infection, usually within 1 to 3 days. Most are treated successfully with antibiotics, sometimes in the hospital.

Trouble passing urineAbout 1 in 100 or fewer

Swelling can block urine for a short time and need a catheter for a few days, more likely with a large prostate.

Fainting

Some men feel lightheaded or faint during or right after the biopsy.

Missing a cancer

A biopsy samples only part of the prostate and can miss a cancer.

Rare

SepsisFewer than 1 in 100

A severe infection that spreads into the blood. It needs emergency treatment and can be life-threatening, which is why fever after this biopsy is always urgent.

Heavy rectal bleeding

Bleeding that needs treatment or a hospital stay is rare.

Allergic reaction

A reaction to the antibiotic, numbing medicine or latex is rare.

Call your care team or go to the emergency room if

Fever of 100.4°F (38°C) or higher, or shaking chills, especially in the first 3 days. Go to the emergency room if you cannot reach your team, and tell them you just had a prostate biopsy.
Feeling very unwell, confused, or dizzy, or a fast heartbeat, even without a measured fever.
You cannot pass urine, or only dribbles, with a full, painful lower belly.
Heavy bleeding from the rectum, or more than a few spoonfuls of blood or clots.
Thick blood or clots in the urine.
Severe or worsening pain in the rectum, between the legs, or in the lower belly.

Questions to ask your surgeon

Why do you recommend a transrectal rather than a transperineal biopsy for me?
What did my MRI show, and will you target any areas?
Which antibiotic will I take, and when?
Do you check a rectal swab before the biopsy?
Should I stop any of my medicines or blood thinners?
Will I be awake with numbing, or can I have sedation?
What temperature should make me call or go to the emergency room?
When and how will I get my results?

Words you may hear

TRUS: Transrectal ultrasound: ultrasound pictures taken from a probe in the rectum.
PSA: Prostate-specific antigen, a protein made by the prostate and measured with a blood test.
PSA density: The PSA level divided by the size of the prostate. Higher values raise the chance of significant cancer.
PI-RADS: A 1 to 5 score for how likely an area on prostate MRI is to be a significant cancer.
Periprostatic nerve block: Numbing medicine placed beside the prostate to reduce pain during the biopsy.
Core: A thin cylinder of prostate tissue taken by the needle.
Fusion biopsy: A biopsy guided by MRI images laid over the live ultrasound.
Grade group: A 1 to 5 scale of how aggressive cancer cells look; 1 is the least aggressive.
Sepsis: A serious, body-wide reaction to an infection in the blood that needs emergency care.
Hematospermia: Blood in the semen.

Common questions

Does it hurt?

With a nerve block, most men describe pressure and brief pinches more than pain. The probe causes a feeling of fullness. Sedation is available in some practices.

Why do I need antibiotics?

The needle passes through the rectum, which contains bacteria. Antibiotics greatly lower, but do not remove, the risk of infection.

Should I ask for a transperineal biopsy instead?

It is a reasonable question. The transperineal route has a lower infection risk, and many centers now use it. Both find cancer at similar rates. Availability, your infection risk and your urologist's experience all matter.

Can a biopsy spread the cancer?

There is no good evidence that a prostate biopsy spreads cancer in any way that matters for your health.

How soon can I go back to normal life?

Most men return to work the same or next day. Avoid heavy exercise and cycling for 2 to 3 days.

Sources this page draws on

American Urological Association and Society of Urologic Oncology, Early Detection of Prostate Cancer: AUA/SUO Guideline (2023)
American Urological Association, White paper on the prevention and treatment of the more common complications related to prostate biopsy
European Association of Urology, EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer
New England Journal of Medicine, PRECISION trial: MRI-targeted or standard biopsy for prostate-cancer diagnosis (2018)
American Cancer Society, Tests to Diagnose and Stage Prostate Cancer

Written November 2026. This page explains what usually happens. It is not medical advice and does not replace a conversation with your own surgeon, whose plan for you comes first.