When urinary tract infection, especially E. coli infection, can reduce nitrate to nitrite, it can cause the urine nitrite positive situation. It is recommended that the patient be further examined and that a urine culture test be performed to clarify the presence of pathogenic bacteria infection, and that the urine routine be observed for elevated white blood cell counts. If the leukocyte count is elevated and the urine is positive for nitrite, the diagnosis of urinary tract infection can be made directly. It can also be combined with the patient’s symptoms. If the nitrite is positive, accompanied by urinary frequency, urinary urgency, back pain and fever, it can also be diagnosed as a urinary tract infection and requires active anti-infection treatment. It is best to conduct a urine culture to clarify the causative organism, because the pathogenic bacteria of urinary tract infections are currently resistant to most antimicrobials, so without the basis of urine culture, the choice of drug-resistant drug treatment may not achieve the therapeutic effect, but will cause the delay or delay of the disease.