Pyelonephritis, also known as upper urinary tract infection, is mostly caused by bacterial infection and the inflammatory response of the urinary system. The screening for this disease involves routine urine tests. Presence of white blood cells in the urine, coupled with symptoms like fever and back pain, can lead to a preliminary diagnosis. However, to confirm the diagnosis and identify the specific infecting pathogen, a culture of midstream urine is needed. Generally, to exclude certain causes of pyelonephritis, it is also necessary for the patient to have blood sugar levels checked and an ultrasound of the urinary system conducted. These tests can confirm whether the patient has diabetes, urinary system stones, or obstructions in the urinary system. Male patients can also undergo a prostate ultrasound to rule out urinary obstruction caused by prostate enlargement. These examinations can also help determine why the patient might have developed pyelonephritis.