Positive urinary nitrite indicates urinary tract infection, which is an indicator of infection in urine examination. Normal urine exists in nitrate, and when there is a urinary tract Enterobacteriaceae infection, it may reduce nitrate to nitrite, which is expressed as positive nitrite. However, the results have a certain false positive rate and need to be combined with leukocyte esterase in urine routine for joint analysis. When the urine is positive for nitrite and leukocyte esterase, it usually indicates enterobacterial infection, and it is recommended to perform a middle urine culture plus drug sensitivity test, which can accurately determine what kind of bacterial infection is, and can screen out antibacterial drugs that are sensitive to this bacteria. If it does not turn negative, it is recommended to continue the treatment for one week for consolidation to avoid the infection from repeatedly lingering or turning into a chronic infection that can affect the quality of life.