How is Kidney Infection Diagnosed?

Many problems in the pelvis and abdomen can cause symptoms that look like kidney infection. Your doctor will want to diagnose your problem correctly to learn what’s happening and find the best treatment.

To diagnose the problem, your health care provider may use the following tests:

  • A medical history. You will be asked questions about your symptoms, when they began, and about your general health history.
  • Physical exam. You will receive a general medical exam to collect blood and urine samples. The doctor will likely press your abdomen to check for pain or tenderness.
  • Urinalysis. A sample of your urine will be tested to look for signs of infection. High counts of white blood cells and bacteria mean that there is an infection.
  • Urine culture. In a urine culture, bacteria in urine may grow on a culture dish within a few days. This information will help the doctor determine the best antibiotic to use.
  • Blood cultures. A blood culture can tell if your infection has spread to your blood.
  • Computed tomography (CT scan). A CT scan is not necessary to diagnose kidney infection, but it shows detailed 3D images of the urinary tract and kidneys to detect problems. A CT would also see if there is a blockage that needs treatment.
  • Kidney ultrasound. Ultrasound can create images of the kidneys and ureters to show if there are wounds, stones, or other things that block the urinary tract. This information can help guide treatment decisions.
  • Voiding cystourethrogram (VCUG) is an x-ray image of the bladder and urethra taken while the bladder is full and during urination. It uses a contrast dye. This test can show problems in the urethra and bladder.
  • Digital rectal examination (DRE). A DRE is a physical exam of the prostate. Men who may have kidney infection may have a DRE to see if a swollen prostate is blocking the neck of the bladder.
  • Dimercaptosuccinic acid (DMSA) scintigraphy. This test uses small amounts of a radioactive material to look closely at how well the kidneys work. Special cameras and computers create images to see if the kidneys are infected, scarred or damaged.

Your doctor will also look for problems that can cause kidney infection, such as kidney stones or birth defects. These things can be treated to prevent future infections. Your treatment will be based on a clear diagnosis of the problem.