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Nuclear renal scan (renogram)

A nuclear renal scan (renogram) is a safe, radiation-based imaging test that shows how well each kidney is working and how urine drains from the kidneys to the bladder — not just what the kidneys look like.

Nuclear renal scan (renogram)
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Updated date
09-10-2026
Reading time
8 mins
Authors
KidneyGlobal Editorial Team
Based on treatment data in this directory
0 verified specialist reviewers

Briefly about this treatment

Indications

Suspected blockage in the urinary tract, unequal function between the two kidneys, monitoring a transplanted kidney, or high blood pressure thought to be caused by a narrowed kidney artery.

Risks

A very small, low-dose radiation exposure, a rare allergic-type reaction to the tracer, and brief discomfort from the IV line. Risks are minimised by careful patient selection, the small tracer dose used, and experienced nuclear medicine teams.

Pre-procedure

Drinking plenty of water beforehand, telling the team about any chance of pregnancy or if breastfeeding, and flagging any blood pressure medications or diuretics you take. No fasting and no anaesthesia consultation needed.

Follow-up

Your ordering specialist reviews the report with you, usually within a few business days, and decides whether a repeat scan or longer-term monitoring is needed — especially for a known blockage or a transplanted kidney.

What is Nuclear renal scan (renogram)? An expert explains

Think of it as a dye-free way to watch your kidneys „in action.” Standard imaging like ultrasound or CT shows the shape of your kidneys. A renogram shows the function — how much blood each kidney filters, and how efficiently urine flows from the kidney, down the ureter, and into the bladder.

The tracer used is a small dose of a radioactive compound (most often technetium-99m MAG3, sometimes DTPA or DMSA) attached to a substance your kidneys naturally clear from the blood. Specialized cameras track the tracer’s movement through the kidneys and urinary system. Depending on what your doctor needs to know, the team may also give a diuretic partway through — a diuretic renogram — which helps tell a true blockage apart from a kidney that’s simply dilated but draining fine. A captopril renal scan uses a blood pressure medication instead, to check for narrowing of the renal artery as a cause of high blood pressure.

It is not used to diagnose CKD on its own, and it does not replace blood or urine tests — it answers a specific question your doctor already has about drainage, blood flow, or one kidney versus the other.

Signs it may be time for Nuclear renal scan (renogram)

Symptoms that might prompt this scan:

  • Unexplained flank or back pain that could point to a blockage.
  • Recurring urinary tract infections, especially in a child.
  • Rising or unexplained abnormal kidney blood tests.
  • High blood pressure that’s proving hard to control.
  • Reduced or uneven urine output, or known swelling in one kidney seen on ultrasound.

These are the conditions linked to this treatment in the directory. Your clinician decides whether a nuclear renal scan is appropriate using your symptoms, examination and test results.

Remember: These entries are not a diagnosis or a treatment recommendation. Discuss your symptoms and test results with a qualified clinician.

 

When to consult a specialist

If you’ve noticed ongoing flank pain, blood pressure that won’t settle, or lab results that don’t quite add up, it’s worth getting it checked — often a simple blood or urine test is the first step, and a scan like this is only ordered if your doctor needs more detail. There’s no need to panic about a scan like this; it’s low-risk and routine for the teams who order it. If you’d like to talk it through with someone qualified, you can find a specialist on KidneyGlobal to discuss whether this test — or another one — is the right next step for you.

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How a session works

  • Check-in and prep. You may be asked to drink water beforehand so you’re well hydrated — this helps the images come out clearly. Most centers don’t require fasting.
  • IV placed. A technologist places a small IV line in your arm or hand.
  • Tracer injected. The radioactive tracer is injected through the IV while you lie on the scanning table, with the gamma camera positioned close to your body.
  • Imaging begins. The gamma camera takes continuous images for about 20–40 minutes while the tracer is taken up by the kidneys, showing how urine flows from the kidneys into the bladder. You’ll need to lie still, but you can breathe normally.
  • Diuretic (if ordered). If your doctor wants to check for a blockage specifically, a diuretic may be given partway through to see how the kidney responds.
  • Bladder-empty image. You may be asked to empty your bladder, then return for one more short image to see how well the bladder empties.
  • Done. The IV is removed and you’re free to leave — no recovery time needed.
Session duration
1–2 hours
recorded for this treatment
Cost verify
$671–$1397
indicative range
Anesthesia
None
recorded for this treatment
Remember: The exact steps, duration and preparation can vary with your indication, health and care setting. Confirm the current plan with your treating team.

Benefits

A nuclear renal scan gives your doctor information that other imaging can’t, with very little burden on you as the patient.

  • Measures each kidney’s function separately, not just combined — this makes it especially useful when only one kidney seems to be struggling.
  • Shows drainage problems that ultrasound and CT often can’t distinguish from normal variation — a dilated kidney that’s draining fine looks different on a renogram than one that’s truly blocked.
  • Very low radiation dose compared with a CT scan.
  • No contrast dye, so it’s a good option if you’re allergic to iodine-based CT contrast.
  • Non-invasive, outpatient, and generally low-discomfort — no incisions, no sedation, and you go home the same day.

Risks & side effects

The treatment has risks and trade-offs to discuss with your care team. The information below comes from this treatment data. A very small, low-dose radiation exposure, a rare allergic-type reaction to the tracer, and brief discomfort from the IV line. Risks are minimised by careful patient selection, the small tracer dose used, and experienced nuclear medicine teams.

  • Most patients experience no side effects beyond the brief needle stick for the IV.
  • If a diuretic is used, you may feel a stronger, more frequent urge to urinate for a few hours afterward.
  • The tracer naturally leaves the body through the urine over the following day.

Who it may not suit: These are general cautions, not a personal verdict. A qualified clinician must assess your full medical picture before recommending or delaying treatment.

  • Pregnancy — generally an absolute reason to avoid the scan, to prevent radiation exposure to the fetus.
  • Breastfeeding — tell the department in advance; a short pause after the injection is often recommended.
  • Dialysis patients — the scan can usually still be done, but timing may need to be coordinated around dialysis.
  • Difficulty lying still (for example, due to pain or anxiety) — let the team know, as this can affect image quality.

 

What happens during & after

During: You’re awake throughout. The scanner is open on the sides (not an enclosed tunnel like an MRI), and a technologist stays nearby the whole time. A radiologist or a doctor specially trained in nuclear medicine interprets the images and sends a report to your referring physician.

After: You can eat, drink and drive as normal. Drinking extra fluids for the rest of the day helps your body clear the tracer faster through your urine. Most of the radioactivity is gone within 24 hours.

Possible complications

True complications are rare. They can include:

  • A small bruise or discomfort at the IV site.
  • A brief flushed feeling or mild nausea if a diuretic is given (uncommon).
  • A rare allergic-type reaction to the tracer — much less common than with iodine CT contrast.
  • A delay in getting a clear result if you’re unable to stay still, are very dehydrated, or have a very full or empty bladder at the wrong moment.
Remember:

New or severe symptoms require prompt medical advice. Do not wait for a routine appointment if you feel seriously unwell.

Recovery

There’s no real recovery period for a nuclear renal scan — most people return to their normal day immediately. Drink extra water for the rest of the day to help clear the tracer, use the toilet regularly, and avoid prolonged close contact with infants or pregnant people for the rest of the day as a simple precaution. A radiologist or nuclear medicine physician reviews the images and sends a report to the doctor who ordered the scan — turnaround is typically a few business days, and your own doctor will explain what the results mean for your care.

Clinics offering Nuclear renal scan (renogram)

Verified kidney centres linked to this treatment in the KidneyGlobal directory.

Massachusetts General Hospital Nephrology Center

Massachusetts General Hospital Nephrology Center

★ Featured✓ Accredited
Academic Medical Center
Comprehensive Nephrology & Transplant
📍 Boston, MA, United States🛏 450 beds🗓 Est. 1955🗣 English, Spanish, French
Joint CommissionMagnet RecognitionUNOS Transplant Center
✓ 24/7 ER✓ ICU✓ Insurance
4,5★★★★★368 reviews
View clinicContact
UCLA Ronald Reagan Medical Center - Urology

UCLA Ronald Reagan Medical Center - Urology

★ Featured✓ Accredited
Academic Medical Center
Minimally Invasive Urologic Surgery
📍 Los Angeles, CA, United States🛏 520 beds🗓 Est. 1981🗣 English, Spanish, French
Joint CommissionNCI Cancer CenterRobotic Surgery Excellence
✓ 24/7 ER✓ ICU✓ Insurance
4,8★★★★★349 reviews
View clinicContact
Jackson Memorial Hospital Kidney Center

Jackson Memorial Hospital Kidney Center

★ Featured✓ Accredited
Public Hospital
Dialysis & Chronic Kidney Disease
📍 Miami, FL, United States🛏 380 beds🗓 Est. 1918🗣 English, Spanish, French
Joint CommissionLevel I Trauma CenterESRD Network Certified
✓ 24/7 ER✓ ICU✓ Insurance
5,0★★★★★207 reviews
View clinicContact
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Good questions

Most Common Questions

Is a nuclear renal scan safe?

Yes, for almost everyone. It uses a very small amount of radioactivity, and most people have no side effects at all beyond the IV needle stick.

Can I have this scan if I'm pregnant or breastfeeding?

Tell the department beforehand if there's any chance you're pregnant — this is generally treated as a reason to avoid the scan. If breastfeeding, most centers ask for a short pause after the injection rather than stopping entirely.

Does it hurt?

No. You'll feel a brief pinch when the IV goes in, then nothing else — the scan itself is painless.

How is this different from a CT or ultrasound?

A CT or ultrasound shows the shape of your kidneys; a renogram shows how well they're functioning and draining — information those scans can't give on their own.

Will I need to stay in the hospital?

No. This is an outpatient test — you go home the same day and resume normal activities right away.

Do I need a follow-up scan?

Sometimes — for example, to track a known blockage over time or monitor a transplanted kidney. Your doctor will tell you if a repeat scan is needed.

Sources

  1. Renal (Kidney) ScintigraphyRadiologyInfo.org (RSNA / ACR)
  2. Renal Scan (Kidney Scan)Cleveland Clinic
  3. Captopril Renal ScanCleveland Clinic
  4. Renal MAG3 ScanCleveland Clinic
  5. MAG3 RenogramKidney Care UK
  6. Nuclear Renal ScanStatPearls (NCBI Bookshelf)