Urinary closure is mostly caused by bacterial infections, and may also be caused by a variety of bacterial mixed infections, so there will be a variety of examination methods, the characteristics and advantages of each method is different, the aspects of the examination will be different. The examination methods: 1, urine routine examination: clean centrifugation of the middle urine sediment in the white cells > 5 / HP, or non-centrifugation of the middle urine white cells > 250 / mm2, that is, suspicious diagnosis of urinary closure. 2, urine culture and colony count: urine culture and colony count is the main basis for the diagnosis of urinary atresia. For asymptomatic girls, a mid-stage urine culture colony count ≥ 105/mL can confirm the diagnosis of urinary closure. 3.Nitrite test: It is a common bacterial urine screening test. E. coli and E. paracolon can reduce nitrate in urine 5.Renal function test: It includes the determination of plasma urea nitrogen, creatinine concentration, creatinine clearance, and urine concentration test. Urine enzyme measurement helps to detect renal tubular function. 6, imaging tests: the purpose is to check whether there are congenital or acquired malformations of the urinary system; urinary closure, vesicoureteral reflux and renal scar formation.