目的　探讨尿S-100B蛋白水平动态变化在早期诊断早产儿脑损伤中的价值。方法　选择2012年1月至12月住院的胎龄<35周的早产儿76例，分别留取生后24、72、120 h尿液，应用化学发光法检测S-100B蛋白含量。根据颅脑超声及磁共振成像(MRI)检查结果，将其分为脑室周围白质软化(PVL)组(16例)、脑室周围及脑室内出血(PVH-IVH)组(20例)及无脑损伤组(40例)，比较各组间S-100B的变化。结果　在生后24、72、120 h各时间点，无脑损伤组、PVL组和PVH-IVH组三组间尿S100B蛋白水平差异有统计学意义(P均<0.01)；在各时间点，均以无脑损伤组最低，PVL组最高，差异有统计学意义(P均<0.01)。PVL组和PVH-IVH组尿S100B蛋白水平随时间点推移的差异有统计学意义(P均<0.01)；均在72 h达到高峰，120 h时有所下降。结论　尿S100-B蛋白水平可作为早期预测脑损伤的敏感标志物，动态监测有助于判断疾病严重程度及评估患儿预后。

　Objective　To investigate the diagnostic value of urine S-100B protein levels in brain injury in premature infants. Methods A total of 76 premature infants with gestational age less than 35 weeks were selected from January to December 2012. Urine samples were obtained at 24 h, 72 h and 120 h after birth, and S-100B protein levels in urine were detected by chemiluminescence. According to the results of cranial ultrasound and MRI, all infants were divided into periventricular leukomalacia (PVL) group (n=16), periventricular-intraventricular haemorrhage (PVH-IVH) group (n=20) and no brain injury group (control group) (n=40). Urine S-100B protein levels were compared among groups. Results There was significant difference in Urine S-100B protein levels among PVL, PVH-IVH and control groups at 24 h, 72 h and 120 h after birth (P<0.01). At each time point, the urine S-100B protein levels were highest in PVL group and lowest in control group, and the differences were significant (P<0.01). The urine S-100B protein levels were significantly different among different time points in PVL and PVH-IVH groups (P<0.01), reaching a peak at 72 h and starting to decrease at 120 h. Conclusions Urine S-100B protein can be used as a sensitive indicator of brain injury in judging disease severity and assessing prognosis.