MCUG (Micturating Cystourethrogram)
The X-ray test that shows urine flowing backwards, and valves in boys.
What is MCUG (Micturating Cystourethrogram)?
The bladder is filled with a contrast liquid through a fine catheter, and X-ray pictures are taken while the child passes urine. It is the only test that reliably shows and grades vesicoureteral reflux, and the definitive test for posterior urethral valves in boys.
- Normal
- Fluid or contrast
Why It Is Asked For
This test is requested only when the answer would change what we do next.
- Repeated urinary infections, especially with fever, in a young child
- A swollen kidney found before or after birth
- A newborn boy with a poor urinary stream
- Before planning surgery for reflux or a ureterocele
Before the Day
- The urine must be free of infection — a culture is usually checked first
- Antibiotic cover is often given around the test
- Bring a change of clothes and a favourite toy; the child can eat normally beforehand
On the Day
- A fine catheter is passed into the bladder — uncomfortable rather than painful, and brief
- Contrast liquid fills the bladder while X-ray images are taken
- More images are taken as the child passes urine, which is the important part
- The whole visit is usually under an hour
What the Results Show
- Reflux is graded from I (mild) to V (severe), and the grade largely decides treatment
- In boys the shape of the urethra shows whether valves are present
- Results are explained to you along with what happens next
Is It Safe?
- It uses X-rays, so the dose is kept as low as possible and the test is only requested when it will change the plan
- Mild stinging on passing urine for a day afterwards is common
- A urinary infection after the test is uncommon and is the reason antibiotic cover is used
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.
Related Pages
MCUG is the only test that grades reflux, and it is worth doing properly.
It is done with antibiotic cover and with a plan for the results agreed beforehand, so the child is not scanned for nothing. Bring the ultrasound report to the appointment.
Consultation 10:00 AM - 1:00 PM & 4:00 PM - 8:00 PM · 24-hour laboratory & pharmacy
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.