High nitrite in the urine indicates the presence of a urinary tract infection and requires further urine culture testing. When an infection occurs in the urinary tract, an infection caused by enterobacteria such as E. coli will reduce nitrite in the urine to a positive level, indirectly indicating the presence of an infection such as E. coli. If E. coli is cultured in the urine culture, the diagnosis can be 100% confirmed and further anti-infection treatment is required. In addition to elevated nitrites, there may also be an elevated white blood cell count or an increased urine protein. The patient’s symptoms, whether they are accompanied by frequent urination, urinary urgency, or lumbar pain, are also used to further aid in the diagnosis. In patients with long-term catheters or cystostomy tubes, elevated urine nitrite may indicate the presence of a catheter-associated infection and require anti-infective treatment.