Abstract:Urinary tract infection is the most common bacterial infection in infancy，and suprapubic puncture is the least contaminated and most accurate method for collecting urine samples. There are some guidelines recommending clean collection of midstream urine， but attention should be paid to identifying false negatives and false positives. Guidelines from multiple countries recommend that pyuria is a necessary condition for diagnosing urinary tract infection，but there are also urinary tract infections without pyuria. The determination of the number of positive bacterial colonies in urine culture varies depending on different urine retention methods，and the standards of different guidelines for the same method are also different. A bacterial colony count as low as 103 -104 CFU/mL in catheterization samples may also indicate urinary tract infection. Therefore，negative urine culture may also indicate urinary tract infection，and there may be even urinary tract infections without pyuria or negative urine culture. When evaluating urinary tract infections in infants，age，gender，clinical symptoms，previous history of urinary tract infections，urine analysis，urine culture，and inflammatory markers （peripheral white blood cell count，C ? reactive protein，and procalcitonin） should be comprehensively considered. If bacterial infection is confirmed，the diagnosis of urinary tract infection should not be easily ruled out after excluding sepsis and bacterial meningitis.