胱抑素C检测及其在各种肾脏疾病患者中的实际应用。

Cystatin C measurement and its practical use in patients with various renal diseases.

作者信息

Tian S, Kusano E, Ohara T, Tabei K, Itoh Y, Kawai T, Asano Y

机构信息

Department of Nephrology, Jichi Medical School, Tochigi, Japan.

出版信息

Clin Nephrol. 1997 Aug;48(2):104-8.

PMID:9285147

Abstract

OBJECTIVE

To evaluate the clinical usefulness in terms of estimation for glomerular filtration rate (GFR), we determined the cystatin C levels in the serum and urine of 33 healthy volunteers as well as in the serum and urine of 35 patients with various renal diseases and compared them with those of creatinine. In addition, we evaluated this substance as an indicator of removal rate of low molecular weight protein with high flux membranes in 6 hemodialysis (HD) patients.

METHODS

Serum and urinary cystatin C levels were measured by using an enzyme-linked immunosorbent assay (ELISA) method, 24-hour creatinine clearance was used as an indicator of GFR.

RESULTS

Reference intervals with 95% ranges are 0.47-1.03 mg/l in the serum from healthy volunteers. There was a significant positive correlation between serum cystatin C and creatinine levels (r = 0.936, p < 0.001) in the patients with various renal diseases. Serum cystatin C and creatinine inversely and logarithmically correlated to creatinine clearance as shown in the following equations: log cystatin C = -0.564 x log creatinine clearance + 1.216 (r = -0.850), log creatinine = -0.678 x log creatinine clearance + 1.449 (r = -0.904). In these equations l/day is the unit used for creatinine clearance, mg/l is the unit used for serum cystatin C. The range for cystatin C is 0.67-6.15 mg/l, 0.66-7.23 mg/dl for creatinine and 8.9-186.3 l/day (6.2-129.4 ml/min) for creatinine clearance. Serum cystatin C levels started to increase over normal range when creatinine clearance fell below 135.9 l/day (94.4 ml/min), while serum creatinine remained within normal ranges. The daily urinary excretion of cystatin C was increased significantly in the group in which creatinine clearance was below 30 l/day (20.8 ml/min) compared to that in which creatinine clearance was higher than in 70 l/day (48.6 ml/min). Fractional clearance of cystatin C increased proportionally and markedly to the decrease of creatinine clearance. In a regular HD condition with high flux membrane, the cystatin C removal rate was 38.7 +/- 1.7%.

CONCLUSIONS

These data suggest that combined measurement of cystatin C in the serum and urine is useful to estimate GFR, especially to detect the mild reduction of GFR. Cystatin C measurement can also be used as an indicator of removal rate of low molecular weight protein with different types of high flux membranes in hemodialysis.

摘要

目的

为评估胱抑素C在估计肾小球滤过率（GFR）方面的临床实用性，我们测定了33名健康志愿者血清和尿液中的胱抑素C水平，以及35名患有各种肾脏疾病患者的血清和尿液中的胱抑素C水平，并将其与肌酐水平进行比较。此外，我们评估了该物质作为6名血液透析（HD）患者中高通量膜对低分子量蛋白质清除率的指标。

方法

采用酶联免疫吸附测定（ELISA）法测量血清和尿液中的胱抑素C水平，将24小时肌酐清除率用作GFR的指标。

结果

健康志愿者血清中95%范围的参考区间为0.47 - 1.03 mg/l。在患有各种肾脏疾病的患者中，血清胱抑素C与肌酐水平之间存在显著正相关（r = 0.936，p < 0.001）。血清胱抑素C和肌酐与肌酐清除率呈反比且对数相关，如下列方程所示：log胱抑素C = -0.564×log肌酐清除率 + 1.216（r = -0.850），log肌酐 = -0.678×log肌酐清除率 + 1.449（r = -0.904）。在这些方程中，肌酐清除率的单位为l/天，血清胱抑素C的单位为mg/l。胱抑素C的范围为0.67 - 6.15 mg/l，肌酐为0.66 - 7.23 mg/dl，肌酐清除率为8.9 - 186.3 l/天（6.2 - 129.4 ml/min）。当肌酐清除率降至低于135.9 l/天（94.4 ml/min）时，血清胱抑素C水平开始超过正常范围，而血清肌酐仍在正常范围内。与肌酐清除率高于70 l/天（48.6 ml/min）的组相比，肌酐清除率低于30 l/天（20.8 ml/min）的组中胱抑素C的每日尿排泄量显著增加。胱抑素C的分数清除率随肌酐清除率的降低而成比例且显著增加。在使用高通量膜的常规血液透析条件下，胱抑素C的清除率为38.7±1.7%。