动态监测血清胱抑素 C 评价肾移植术后肾功能的改变

目的 监测肾移植受者血清胱抑素C(Cys C)浓度以评估移植肾功能的改变. 方法 监测58例肾移植成功受者术前及术后不同时间的血清Cys C、肌酐(SCr)、β2-微球蛋白(β2-MG)和尿素氮(BUN)水平;并于术后第7天使用99mTc-DTPA测定受者肾小球虑过滤(GFR),比较其与上述四项指标的相关性.以GFR=1.5 ml/s为临界值,绘制ROC曲线,比较各项检测指标鉴别轻度与中重度肾功能损伤的诊断性能.计算受者不同时间段血清Cys C及SCr变异系数及其比值(R值). 结果 Cys C于术后第1天下降达48.1%,明显大于其他指标的下降幅度.血清Cys C、SCr、β2-MG和BUN与GFR相关系数依次为0.876、0.691、0.589和0.516.血清Cys C、SCr、β2-MG和BUN的诊断性能:敏感性分别为91.3%、87.2%、82.6%和87.0%;特异性分别为80.0%、69.2%、71.4%和42.9%;阳性预期值分别为82.0%、73.7%、74.3%和60.4%;阳性似然比分别为4.81、2.83、2.87和1.53;ROC曲线下面积(AUC)分别为0.914、0.828、0.803和0.765.SCr的变异系数显著小于Cys C(P＜0.01),Cys C＜2 mg/L的受者R值大多＜1,Cys C＞2 mg/L的受者,伴随Cys C水平升高,R值趋近于1. 结论 Cys C与GFR相关性最好;Cys C的诊断性能及准确性均优于其他指标,即使肾功能有微小损伤,Cys C也会有显著改变.因此,肾移植术后动态监测Cys C对于及时判断移植肾存活及肾微小损伤时肾功能的改变优于其他指标.     

血清胱抑素C在肾移植患者肾功能监测中的作用

近年来的研究表明,血清胱抑素C在反映移植肾滤过功能方面优于血清肌酐等传统的检验项目,有助于更及时地发现急性排斥反应或药物性肾中毒。血清胱抑素C测定方法简便、迅速、价格适中,适合临床应用。     

肾移植患者血清胱抑素C与肌酐清除率相关性的研究

目的探讨肾移植患者血清胱抑素C（SCysC）浓度作为移植肾功能测定指标的可行性和临床应用价值。方法采用颗粒增强透射免疫比浊法（PETIA）分别检测39例初次肾移植患者在术前、术后1周和4周的SCysC水平,并与血清肌酐（Scr）、内生肌酐清除率（Ccr）进行比较分析。结果肾移植术前与术后,患者的SCysC与Scr、Ccr都具有很好的相关性。SCysC与Scr呈正相关（术前r=0.849;术后r=0.940）;与Ccr呈负相关（术前r=-0.857;术后r=-0.876）;按Ccr分组的统计分析结果显示：不同肾功能水平的SCysC与Ccr的相关性均较Scr与Ccr的相关性相似或更佳。当50≤Ccr〈80mL/（min.1.73m^2）时,SCysC与Ccr的相关性要明显优于Scr与Ccr的相关性（P〈0.05）。结论在肾移植患者中,SCysC浓度与Scr浓度和Ccr有较好的相关性,可成为评估移植肾功能的较理想指标。     

血清胱抑素C：在肌酐盲范围检测GFR的标志物

近年来实验和临床研究表明，血清中胱抑素与传统的血肌酐测定相比，是更好的检测肾小球滤过率（GFR）的标志物，对它的检测拟可作为早期而敏感的GFR指标。     

血清胱抑素C:在肌酐盲范围检测GFR的标志物

近年来实验和临床研究表明 ,血清中胱抑素与传统的血肌酐测定相比 ,是更好的检测肾小球滤过率 (GFR)的标志物 ,对它的检测拟可作为早期而敏感的GFR指标。     

血清胱抑素C在评价慢性肾脏病患者肾小球滤过率中的价值

目的：探讨血清胱抑素C（CystC）在评价慢性肾脏病（CKD）患者肾小球滤过率中的临床价值。方法：选取2009年4月～2009年11月住院的CKD患者76例,检测其血清CystC浓度,血清肌酐浓度（Scr）,以99mTc-二乙三胺五醋酸（99mTc-DTPA）法测定肾小球滤过率（GFR）,并用简化MDRD和Cockcroft-Gault（C-G）方程分别估测GFR（M-GFR,C-GFR）,以99mTc-GFR作为金标准,比较不同CKD分期间各指标间的相关性及其敏感度和特异度。结果：患者血清CystC、Scr、C-GFR、M-GFR与99mTc-GFR的相关系数分别为-0.81、-0.73、0.90、0.89,P均〈0.01,CystC在CKD1～3期与99mTc-GFR均有相关性,相关系数分别为-0.57（P〈0.05）,-0.44（P〈0.05）,-0.74（P〈0.01）,但在4～5期两者无明显相关关系（相关系数-0.30,P〉0.05）而Scr、C-GFR、M-GFR与99mTc-GFR仅在CKD3期患者中有相关性;在CKD1期患者中,CystC的敏感性和特异性均高于C-GFR和M-GFR。结论：血清CystC是一个反映CKD患者肾功能的较为敏感的指标,尤其在早期CKD患者中应用价值更大。     

血清胱抑素-C是反映肾小球滤过功能的敏感指标

目的探讨测定血清胱抑素C(Cystatin C)浓度来判断肾小球滤过率的准确性与敏感性。方法对32例各种原因可能或已经肾功能轻-中度受损的患者，应用乳胶颗粒增强比浊法(PET)测定其血清CystatinC浓度，采用^99Tc-DTPA血浆清除率测定其肾小球滤过率(GFR)，同时测定血尿素氮(BUN)、血肌酐(SCr)，并根据Cockcroft-Cault公式计算肌酐清除率。结果血清Cystatin C浓度与上述指标均有相关性，并有显著性意义。血清Cystatin C比SCr与用^99Tc-DTPA测定的GFR有更好的一致性。结论血清Cystatin C浓度是一个反映肾小球滤过功能准确、敏感的指标。     

以血清胱抑素C评价早期肾功能损害的临床研究

目的:评价血清胱抑素C(Cystatin C)在早期肾功能损害诊断中的临床意义.方法:应用ELISA法测定84例各种肾脏病患者的血清胱抑素C浓度,同时测定血清肌酐(Scr,Jaffe法)及肌酐清除率(Ccr),以放射性核素99m Tc-DTPA测得的GFR作为诊断评价的金指标,比较Cystatin C、Scr、Ccr与GFR的相关性,采用受试者工作特征曲线下面积(AUCROC)和似然比(LR)评价Cystatin C的可靠性.结果:血清Cystatin C、Scr、Ccr与GFR均呈显著相关(P<0.01),且以Cystatin C与GFR的相关程度最密切;上述三个指标AUCROC分别为0.989、0.926、0.942,且Cystatin C与Scr之间具有显著统计学意义(P<0.05),而与Ccr间无统计学差异(P>0.05),LR以血清Cystatin C为最佳.结论:血清Cystatin C 是一个更为准确、可靠的反映肾小球滤过功能的指标,对诊断各种不同肾脏病患者早期肾功能损害具有指导意义.     

血清胱抑素C:一种简便的肾小球滤过率指标

肾小球滤过率(glomerular filtration rate,GFR)是反映肾功能最重要的指标.目前临床上常用来反映肾小球滤过功能的指标如血肌酐(Scr)、内生肌酐清除率(Ccr)等都有一定的局限性,且不同程度地受到一些肾内或肾外因素的干扰.为此寻找新方法来测定肾功能,是众所关心的问题.近年来,测定血清胱抑素C(Cystatin C)来反映GFR水平,受到人们关注.     

240例肾脏疾病患者血清胱抑素C的变化及临床相关研究

我们检测240例肾脏疾病患者血清胱抑素C(Cystatin C)浓度,试图发现血清Cystatin C浓度与肾小球滤过率之间的关系,且与血尿素氮、血肌酐、内生肌酐清除率对照观察,探讨血清 Cystatin C浓度变化对判断肾小球滤过功能是否受损及受损程度的应用价值,且与临床相关性作一研究.     

应用血清西司他汀浓度测定肾小球滤过率的相关研究

目的：提供临床上准确，简便测定肾小球滤过率的方法。方法：应用乳胶颗粒增强比浊法（PET）测定79例有肾脏损害患者血清西司他汀（cystatin C)浓度，同时测定血尿素氮（BUN），血肌酐（Scr),24h肌清除率（24h Ccr)和采用Cockcroft-Cault公式计算肌酐清除率（Ccockcroft)，结果除BUN外，以上指标与cystatin C均有相关关系，并有显著性意义。结论：cystatin C浓度检测在临床上提供一种快速，准确和简捷的测定肾小球滤过率的方法，能发现早期肾脏损害和肾功能改变。     

移植肾肾小球滤过率的检测和评估（附视频）

探讨评估移植肾肾小球滤过率（GFR）的最佳方法,从而早期发现移植肾功能异常并适时干预,对提高肾移植受者的生活质量和长期存活具有重要意义。本文介绍了菊粉清除率、放射性核素法实测GFR,应用外周血清肌酐、血清尿素氮、肌酐清除率等间接评估GFR,以及通过公式估算GFR等各种目前常见的GFR评估方法的原理及其优劣;并根据肾移植受者的特殊情况分析了估算GFR公式的适用性。     

肾移植术后一年时的肾小球滤过率与移植肾长期功能的相关性研究

目的 探讨肾移植受者术后1年时的肾小球滤过率(GFR)与移植肾长期功能的相关性. 方法 回顾性分析1994年11月至2004年10月间334例肾移植受者的临床资料.根据术后1年时的GFR不同,将受者分成肾功能正常组(≥1.083 ml/s; 267例)和肾功能异常组(GFR＜1.083 ml/s;67例))GFR采用Coekeroft-Gault(C-G)公式进行计算.采用Kaplan-Meier方法比较两组受者术后5年时移植肾的长期存活率;分析术后1年与术后5年时GFR的相关性. 结果 肾移植术后移植肾存活率呈现逐年下降趋势,术后1年时的GFR与移植肾存活时间成正比,术后同一时间点(5年、10年),肾功能正常组(不包括或包括肾功能正常的死亡者)移植.肾的长期存活率均高于肾功能异常组,两组比较,差异有统计学意义(P＜0.05).与术后1年时GFR比较,术后5年时的GFR变化幅度为(0.080±0.248)ml/s,其下降程度与术后1年时的GFR呈现明显正相关性. 结论 术后1年时的GFR水平影响移植肾的长期功能,术后1年时的GFR越高,术后5年的GFR也越高.     

Clinical assessment of serum cystatin C as a marker of glomerular filtration rate in patients with various renal diseases

Background. Recent reports have raised questions about the validity of estimating glomerular function and changes in glomerular function from measurements of serum creatinine. To evaluate the clinical usefulness of serum creatinine levels in terms of estimation of glomerular filtration rate (GFR), we determined serum cystatin C levels in 152 patients with various renal diseases and compared them with serum creatinine levels. Methods. Serum cystatin C levels were measured by particle-enhanced immunonephelometry. Two-h creatinine clearance (Ccr) was used as an indicator of GFR. Results. There was a significant positive correlation between serum cystatin C and creatinine levels (r = 0.941) in patients with various renal diseases. Serum cystatin C and creatinine were inversely correlated to Ccr. The overall correlation between serum cystatin C and Ccr was slightly stronger than that between serum creatinine and Ccr. In the patient group with a critical Ccr level (Ccr, 60–80 ml/min per 1.48 m²), the correlation between the reciprocal serum cystatin C levels and Ccr (r = 0.441) was significantly stronger (P < 0.01) than that between the reciprocal serum creatinine levels and Ccr (r = 0.212). A mild reduction of Ccr was detected more easily by serum cystatin C than by serum creatinine, as the clinical sensitivity and specificity of serum cystatin C were superior to that of serum creatinine. Conclusions. The cystatin C assay by particle-enhanced immunonephelometry was found to be a sensitive, fully automated, and rapid method. Serum cystatin C appears to be a promising marker of GFR in patients with impaired renal function. Its diagnostic potential was slightly superior to that of serum creatinine in adults with various renal diseases. Received: October 7, 1998 / Accepted: November 4, 1999     

Assessment of glomerular filtration rate in renal transplant patients using serum cystatin C

AIM: Serum cystatin C (SCysC) has been proposed as a better marker of glomerular filtration rate (GFR) than serum creatinine (Scr). However, few data are available in renal transplant patients, especially, during the early postoperative phase. METHODS: Thirty-nine renal transplant patients (22 men/17 women) were recruited for determination of SCysC and Scr before operation, at 1 week and at 4 weeks after operation. SCysC was determined by particle-enhanced turbidimetric immunoassay. Creatinine clearance (Ccr) was calculated using the Cockcroft-Gault formula. RESULTS: SCysC and Scr levels significantly decreased with the recovery of allograft function. SCysC showed a significant correlation with Scr and Ccr. The relationship between SCysC and Scr showed a positive correlation (r = .849 preoperation, and r = .940 postoperation). The relationship between SCysC and Ccr revealed a negative correlation (r = .857 preoperation, and r = .876 postoperation). At the Ccr level of 50 to 80 mL/min/1.73 m(2), the correlation between SCysC and Ccr (r = .778) was significantly better than that between Scr and Ccr (r = .553; P = .032). The concentration of SCysC was not affected by age, gender, height, body weight, hemoglobin, serum protein, glucose, or mycophenolate mofetil or azathioprine dosage. However, corticosteroids slightly increased the level of SCysC and cyclosporine (CsA) decreased it. The area under the curve of the receiver operating characteristic curve for SCysC and Scr are 0.964 and 0.915, respectively (P < .05). CONCLUSION: Although the concentration may be slightly influenced by prednisolone and CsA, SCysC is more sensitive than Scr to detect early and moderate deterioration of GFR in adult renal transplant recipients.     

Rapid and accurate assessment of glomerular filtration rate in patients with renal transplants using serum cystatin C.

BACKGROUND: Assessment of renal function in patients with renal transplants is of great importance. Various studies have reported cystatin C as an easily and rapidly assessable marker that can be used for accurate information on renal function impairment. To date, no study is available to define the role of cystatin C in patients with renal transplants. METHODS: Thirty steady-state patients (50% male/50% female) with status post-kidney transplantation were studied. To assess renal function, cystatin C, creatinine clearance, serum creatinine, beta2-microglobulin (beta2M), and [125I]iothalamate clearance were determined. Correlations and non-parametric ROC curves for accuracy, using a cut-off glomerular filtration rate (GFR) of 60 ml/min, were obtained for the different markers allowing for calculations of positive predictive values (PPV), positive likelihood ratios (PLR), specificity and sensitivity, respectively. Further, to evaluate the usefulness of these markers for monitoring, intraindividual coefficients of variation (CVs) for cystatin C and creatinine measurements were compared in 85 renal transplant patients. Measurements consisted of at least six pairs of results, which were obtained at different time points during routine follow-up. RESULTS: Cystatin C correlated best with GFR (r=0.83), whereas serum creatinine (r=0.67), creatinine clearance (r=0.57) and beta2M (r=0.58) all had lower correlation coefficients. The diagnostic accuracy of cystatin C was significantly better than serum creatinine (P=0.025), but did not differ significantly from creatinine clearance (P=0.76) and beta2M (P=0.43). At a cut-off of 1.64 mg/l, cystatin C has a PPV of 93%, PLR of 6.4, specificity 89% and sensitivity 70%, respectively. For beta2M, PPV 83%, PLR 1.7, specificity 67% and sensitivity 75% was seen at a cut-off of 3.57 mg/l. Accordingly, at a cut-off of 125 micromol/l for serum creatinine, a PPV 76%, PLR 1.4, specificity 44% and sensitivity 80% was revealed. Finally, at a cut-off of 66 ml/min/1.73 m2 for creatinine clearance, the following characteristics were found: PPV 94%, PLR 7.7, specificity 89% and sensitivity 85%. The intraindividual variation of creatinine was significantly lower than that of cystatin C (P<0.001). With increasing concentrations, their ratios of CV tended towards a value of 1, demonstrating identical variability at low GFR. CONCLUSION: Together, our data show that in patients with renal transplants, cystatin C, in terms of PPV and PLR, has a similar diagnostic value as creatinine clearance. However, it is superior to serum determinations of creatinine and beta2M. The intraindividual variation of cystatin C is greater than that of creatinine. This might be due to the better ability of cystatin C to reflect temporary changes especially in mildly impaired GFR, most critical for early detection of rejection and other function impairment. Thus, cystatin C allows for rapid and accurate assessment of renal function (GFR) in renal transplants and is clearly superior to the commonly used serum creatinine.     

Comparison of serum cystatin C and creatinine levels in determining glomerular filtration rate in children with stage I to III chronic renal disease

Abstract

Background: Pediatric studies are relatively scarce on the superiority of cystatin C over creatinine in estimation of glomerular filtration rate (GFR). This study measured cystatin C and serum creatinine levels, and compared GFR estimated from these two parameters in patients with chronic renal disease. Methods: This prospective, observational, controlled study included 166 patients aged 1–18 years diagnosed with stage I to III chronic renal disease, and 29 age- and sex-matched control subjects. In all patients, GFR was estimated via creatinine clearance, Schwartz formula, Zappitelli 1 and Zappitelli 2 formula and the results were compared using Bland–Altman analysis. Results: Patients and controls did not differ with regard to height, body weight, BMI, serum creatinine and serum cystatin levels, and Schwartz formula-based GFR (p?>?0.05). There was a significant relationship between creatinine and cystatin C levels. However, although creatinine levels showed a significant association with age, height, and BMI, cystatin C levels showed no such association. ROC analysis showed that cystatin C performed better than creatinine in detecting low GFR. Conclusion: Cystatin C is a more sensitive and feasible indicator than creatinine for the diagnosis of stage I to III chronic renal disease.     

Measurement of glomerular filtration rate in renal transplant recipients: A comparison of methods

SUMMARY: While single injection radionuclide and radio‐contrast glomerular filtration rate (GFR) clearance methods are widely used, the relative accuracy of single versus multiple sample techniques continues to be debated. In addition, GFR calculated from the serum creatinine concentration is considered by some to produce results comparable to clearance methods. In this study, 109 patients with stable renal transplant fraction were prospectively evaluated by yearly ⁵¹Cr EDTA clearance as well as by three published formulae used to predict GFR from serum creatinine. Analysis of 362 measurements demonstrated a highly significant correlation between multiple and single point clearance results, as well as the serum creatinine nomograms using least squares regression analysis (P<0.001). the mean GFR was, however, significantly higher using the Cockcroft and Gault formula; 64 ± 18 compared with 47 ± 14 and 50 ± 14 with other serum creatinine formulae, and 46 ± 21–50 ± 17mL/min per 1.73m2 with the three ⁵¹Cr EDTA methods (P<0.01). However, further statistical analysis using more appropriate methods, including an analysis of difference and least product regression analysis did not support any of the methods tested as reliable alternatives to multiple sample ⁵¹Cr EDTA clearance, because both fixed and proportional bias was noted. In a subgroup of 29 patients evaluated yearly over the 7‐year study period, serum creatinine derivations all demonstrated a greater year to year mean fluctuation compared with clearance methods. It is oncluded that while each GFR method has similarities, they are not interchangeable. Until clearance methods and serum creatinine formulae are directly compared with inulin clearance with the use of appropriate statistical evaluation, it is recommended that the Chantler 3 sample ⁵¹Cr EDTA method be the method of choice in clinical laboratories.