Kjaergaard Krista D, Rehling Michael, Jensen Jens D, Jespersen Bente
Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark.
Clin Physiol Funct Imaging. 2013 May;33(3):224-32. doi: 10.1111/cpf.12018. Epub 2013 Jan 1.
Residual renal function in haemodialysis patients is of increasing interest. However, reproducibility and agreement between methods to measure and estimate glomerular filtration rate (GFR) require further elucidation. The aim of this study was to evaluate the accuracy and reproducibility of GFR estimates based on endogenous markers in haemodialysis patients.
Twelve patients were examined twice. GFR was estimated by (i) urine clearances of creatinine, urea and the average of creatinine and urea clearance [U-Cl(crea-urea)]; (ii) an equation based on serum concentration of cystatin C [eGFR(CysC)]. These were compared to (51) Cr-EDTA clearance in plasma [P-Cl(EDTA)] and urine [U-Cl(EDTA)].
U-Cl(crea-urea) produced results similar to U-Cl(EDTA). eGFR(CysC) had a low week-to-week variability. Visually, eGFR(CysC) differed from y = x when compared to the other methods indicating bias, probably due to extrarenal elimination of cystatin C. Coefficients of variation were significantly different, P<0·001: P-Cl(EDTA), 10%; U-Cl(EDTA), 13%; and U-Cl(crea-urea), 13%. P-Cl(EDTA) was 2·1 ml min(-1) 1·73 m(-2) higher than U-Cl(EDTA) (mean).
Glomerular filtration rate in haemodialysis patients can be estimated from U-Cl(crea-urea) when complete urine collection is performed. The available eGFR(CysC) in haemodialysis patients seemed to be biased, and further development and validation is desirable. P-Cl(EDTA) was the most reproducible method and might be useful in special situations.
血液透析患者的残余肾功能越来越受到关注。然而，测量和估算肾小球滤过率（GFR）的方法之间的可重复性和一致性需要进一步阐明。本研究的目的是评估基于内源性标志物估算血液透析患者GFR的准确性和可重复性。
对12例患者进行了两次检查。通过以下方法估算GFR：（i）肌酐、尿素的尿清除率以及肌酐和尿素清除率的平均值[U-Cl（肌酐-尿素）]；（ii）基于血清胱抑素C浓度的公式[eGFR（CysC）]。将这些结果与血浆[P-Cl（EDTA）]和尿液[U-Cl（EDTA）]中的（51）Cr-EDTA清除率进行比较。
U-Cl（肌酐-尿素）产生的结果与U-Cl（EDTA）相似。eGFR（CysC）的周间变异性较低。直观上，与其他方法相比，eGFR（CysC）与y = x不同，表明存在偏差，可能是由于胱抑素C的肾外清除。变异系数有显著差异，P<0·001：P-Cl（EDTA）为10%；U-Cl（EDTA）为13%；U-Cl（肌酐-尿素）为13%。P-Cl（EDTA）比U-Cl（EDTA）平均高2·1 ml min（-1）1·73 m（-2）。
当进行完整的尿液收集时，可通过U-Cl（肌酐-尿素）估算血液透析患者的肾小球滤过率。血液透析患者中现有的eGFR（CysC）似乎存在偏差，需要进一步开发和验证。P-Cl（EDTA）是最具可重复性的方法，可能在特殊情况下有用。
