Testing & Diagnosis for Ureteropelvic Junction (UPJ) Obstruction in Children


How is a UPJ obstruction diagnosed?

  • A UPJ obstruction can often be diagnosed before birth if your doctor sees too much urine in your developing baby’s kidney—a condition called hydronephrosis—during a prenatal ultrasound study. This accumulation of urine in the kidney can be caused by a UPJ obstruction that blocks the flow of urine from the kidney.
  • If an ultrasound indicates that your child has hydronephrosis, your obstetrician may monitor your pregnancy more closely and may perform more ultrasounds to check for any changes over time.
  • The good news is that often these blockages don’t cause any problems—and many go away on their own without any treatment. 

If hydronephrosis has been seen during a prenatal ultrasound, your doctor will typically perform the following tests within a few weeks after your baby is born: 

  • Renal ultrasound: Your new baby will have her own ultrasound test to look at the kidneys. This study gives a good picture of how serious the hydronephrosis is.
  • Voiding cystourethrogram: This special kind of X-ray is used to show the anatomy of your child’s bladder and urethra. Using a small tube called a catheter, doctors will fill your child’s bladder with a liquid containing iodine. As the bladder fills and your child urinates, the flow of the liquid will be visible on video X-ray images.
  • Renal scan: This test helps to measure the difference in function between the two kidneys and estimate the degree of blockage in the urinary system. After a tiny amount of radioactive material (radioisotope) is injected into your child’s bloodstream, a special camera called a gamma camera is used to take pictures of the kidneys, showing how well they are filtering and draining.
  • Blood tests: These let the doctor see how well your child’s kidneys are working.
  • Urinalysis and urine culture:  Laboratory tests that examine the urine. These tests can indicate microscopic blood or protein in the urine, other chemicals, or evidence of a UTI. 

After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options for your child.