尿液甘氨酰脯氨酸二肽氨基肽酶测定及临床应用

Measurement of glycyl-proline dipeptidyl aminopeptidase in urine and its clinical application

目的 探讨尿液甘氨酰脯氨酸二肽氨基肽酶 (GPDA)测定及临床应用价值。方法 用连续监测法以甘氨酰脯氨酰对硝基苯胺为底物检测尿液GPDA ,并对检测条件及干扰因素进行试验探讨 ,同时对 334名正常人 ,5 5例糖尿病和 36例高血压患者尿液GPDA进行检测分析。结果 尿GPDA在 35 0U/L以下线性良好 ,低、高值尿液标本的批内变异系数 (CV)分别为 1 2 7%、0 6 1% ,批间CV为 1 33% ,尿液标本 4℃存放 7dGPDA活性没有变化 ,胆红素、葡萄糖、维生素C及糖尿病治疗药物二甲双胍、格列苯脲对GPDA测定无干扰 ,血红蛋白在 5 0 0mg/L以下时对GPDA测定无干扰 ,>5 0 0mg/L产生负干扰 ,334名正常人尿GPDA活性为 (12 9± 4 1)U/g·Cr,参考值范围 4 9～ 2 0 9U/g·Cr;糖尿病、高血压病合并肾损害组尿GPDA明显高于正常对照组和未发生肾损害组 ,差异有非常显著意义 (P <0 0 0 1)。结论 甘氨酰脯氨酸二肽氨基肽酶操作简单、快速、稳定性好 ,干扰因素少 ,结果准确 ,是诊断早期肾小管损伤的敏感而特异的检验项目。

Objective To study on the measurement of glycyl-proline dipeptidyl aminopeptidase (GPDA) in urine and its clinical application. Methods GPDA in urine was measured by continuously monitoring method using substrate. The assay conditions and interference factors were investigated. GPDA activities in urine specimens from 334 healthy persons, 55 diabetes mellitus patients and 36 hypertension patients were measured. The differences between the kidney injured and non-kidney injured groups were analyzed. Results The linearity of the method was up to 350 U/L. The intra CV and inter CV were 1.27% and 1.33% respectively. The GPDA activity in urine specimen was stable for 7 days at 4℃. There was no interference of bilirubin, glucose, vitamins, dimethylbiguanide and gliben-clamide. No significant interference was found by hemoglobin less than 500 mg/L. GPDA level in urine specimens of 334 healthy persons were (12.9±4.2) U/g·Cr. The GPDA levels of diabetes mellitus and hypertension groups combined with kidney injured were obviously higher than that of the control group and the non-kidney injured group ( P <0.001). Conclusions The assay is simple, rapid, stable and has no significant interference factors. It′s suitable for auto-analyzer and routine measurement. It is a sensitive and specific item in early diagnosis of uriniferous tubules injured.