Diuretic Renogram (MAG3 / DTPA)
The test that proves whether a swollen kidney is genuinely blocked.
What is Diuretic Renogram (MAG3 / DTPA)?
A tracer is given through a vein and a camera follows it through the kidneys. A diuretic is then given, and how quickly the tracer washes out shows whether urine is genuinely obstructed or simply sitting in a roomy system.
- Normal
- The problem
- Healthy for comparison
Why It Is Asked For
This test is requested only when the answer would change what we do next.
- To decide whether hydronephrosis is caused by a true blockage
- To measure the split function of each kidney before considering pyeloplasty
- To follow a kidney after surgery and confirm drainage has improved
Before the Day
- Good hydration is important — the child may be asked to drink beforehand or be given fluids
- A bladder catheter is sometimes used so a full bladder does not distort the result
- Allow two to three hours for the visit
On the Day
- A cannula is placed and the tracer given
- The child lies on the camera bed for around 30 to 40 minutes
- A diuretic is given partway through and images continue
What the Results Show
- Reports split function and a drainage curve for each kidney
- Free drainage after the diuretic argues against obstruction
- Delayed drainage with falling function is the clearest indication for surgery
Is It Safe?
- A small radiation dose, kept as low as possible
- The diuretic makes the child pass more urine for a few hours afterwards
- The cannula is the part children mind most; numbing cream helps
Common Questions
If your question is not here, send it on WhatsApp and the hospital team will answer.
Dr. Pratheep Samraj
Consultant Paediatric & Neonatal Surgeon · Palliyadi, Kanyakumari
Super-specialist surgical care for newborns, infants and children, with expertise in paediatric urology, congenital anomalies, gastro-intestinal surgery and minimally invasive surgery.
A renogram is what separates a roomy kidney from a blocked one.
It is the test that should come before anyone offers your child a pyeloplasty. Bring the ultrasound reports, including the antenatal ones if you still have them.
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In an emergency — green vomiting in a baby, a groin swelling that will not go back, severe tummy pain, or a newborn not passing urine or meconium — come straight to the hospital or to your nearest emergency department. Do not wait for a reply to a message.