尿NHE3在急性肾损伤早期诊断中的价值

目的 探讨尿Na＋/H＋交换体亚型3（Sodium Hydrogen exchanger isoform 3,NHE3）在重症监护（ICU）患者急性肾损伤（acute renal injury,AKI）早期诊断中的价值.方法 前瞻性选择入住ICU的100例患者,每天收集血、尿标本,用酶法测定血清肌酐（Scr）,ELISA法测定尿NHE3水平,计算肾小球滤过率（GFR）,根据有无合并AKI将患者分成AKI组和非AKI组,并与30例健康体检者作为正常对照组进行比较.采用ROC曲线评价尿NHE3诊断AKI的临床价值.结果 三组尿NHE3基线水平无明显差异,非AKI组Scr、GFR、尿NHE3水平无明显变化,AKI组尿NHE3水平显著升高,升高时间较Scr提前24 h.尿NHE3与Scr呈正相关、与GFR呈负相关（r=0.457,-0.463,P均〈0.05）.以Scr升高〉50%或血肌酐升高绝对值≥26.4 μmol/L作为AKI的诊断标准,NHE3灵敏度和特异度绘制ROC曲线,曲线下面积（AUC）为0.758,与完全随机情况下获得的AUC=0.5差异有统计学意义（P〈0.05）.以NHE3升高〉50%基础值作为AKI的诊断界限时,敏感度和特异度分别为67.9%和88.9%,阳性预测值和阴性预测值分别为70.4%和87.7%.结论 尿NHE3表达较Scr更早发生变化,可作为ICU患者AKI早期预测指标.

Prospective study of the early diagnosis value of urinary NHE3 in acute renal injury

Objective To study the early diagnosis value of urinary NHE3 in acute renal injury （AKI）. Methods One hundred critically ill patients hospitalized in intensive care unit were enrolled in the study. Thirty health people were included as the control group. Urinary and blood samples were collected daily. Serum creafinine was detected by enzymic method, urinary NHE3 was detected by ELISA. AKI was defined as the absolute increment over ≥26. 4 μmol/L or 50% increased of serum ereatinine from the baseline. Results Twenty-eight of the 100 patients developed AKI. The baseline levels of serum creatinine and urinary NHE3 were similar in three groups. Urinary NHE3, Scr, GFR were no changed in non-AKI group. Urinary NHE3 in AKI group was significantly higher than baseline （ P 〈 0. 05） 24 h before AKI diagnosed. According to the sensitivity and specificity of NHE3, ROC curves were drawn：ROC analysis confirmed diagnostic accuracy for NHE3 in AKI, area covered under the AUC curve was 0. 758（95% CI： O. 635 -0. 804, P 〈0.05）. With the cut-of value of NI-IE3 increased≥50%, the diagnostic sensitivity and specificity in AKI were 67.9% and 88.9%, the positive predictive value and negative predictive value were 70. 4% and 87.7% respectively. Conclusion Urinary NHE3 can diagnose AKI earlier than Ser in ICU patients, which may be a good biomarker for early diagnosis of AKI.