碘海醇清除率--一种新的测定肾小球滤过率的方法

目的 验证新的测定肾小球滤过率（GFR）的方法--碘海醇清除率作为判断GFR的临床意义。方法 对19例不同肾功能的患者同时进行^99mTc-DTPA清除率及碘海醇清除率的测定,以^99mTc-DTPA清除率为标准方法,对两组结果进行相关分析。血、尿标本中碘海醇的测定采用X-射线荧光分析法。结果 碘海醇清除率与^99mTc-DTPA清除率高度相关性（r=0.98）。结论 碘海醇清除率是一种安全、可靠、无放射性的测定GFR的方法。     

测定慢性肾小球肾炎患者肾小球滤过率的三种方法比较

目的　为准确评估慢性肾小球肾炎（CGN）患者的肾小球滤过率（GFR）提供依据。 方法　对42例CGN患者同时采用双血浆法（tGFR）、肾动态显像法（dGFR）与24 h肌酐清除率法（24hCcr）测定GFR。tGFR为金标准,与另2种方法结果进行比较,若差异有统计学意义则进行相关和回归分析,同时比较肾动态显像法测定分肾GFR的差异。 结果　24hCcr、dGFR均与tGFR的差异有统计学意义（P值分别为0.001和0.045）;但其相关性均较好,相关系数分别为0.916（P = 0.000）和0.957（P = 0.000）,且均与tGFR呈直线相关关系,其直线回归方程分别为tGFR=0.936 dGFR-4.648（F = 208.941,P = 0.000）和tGFR=0.887 24hCcr+2.919（F = 376.513,P = 0.000）。肾动态显像法所测分肾功能的差异无统计学意义（P = 0.882）。 结论　24hCcr、dGFR均不能代替tGFR,但两种方法均能够较准确、安全、有效地反映CGN患者的GFR,且CGN患者双肾GFR呈同步下降。因此,在缺少SPECT的医院,临床上可选24hCcr法测定CGN患者的GFR。     

放射性核素血浆标本法肾小球滤过率测定的质量控制

肾小球滤过率(GFR)是检测肾脏滤过功能的一项重要指标,但除了肾功能水平外GFR受很多因素影响.我科于1995年起采用国际上推荐的双血浆标本法测定GFR[1],本文对影响该方法的因素包括99Tcm-DTPA 注射剂量、不同条件下测定CPM、性别及体表面积等进行了质量控制方面的探讨,报告如下.     

碘海醇血浆清除率测定肾小球滤过率与临床常用的估算肾小球滤过率方法的比较

目的采用碘海醇血浆清除率测定肾小球滤过率(mGFR)与临床常用方法评估估算肾小球滤过率(eGFR)的准确性比较。方法选取2019年6月至2020年6月在本院自愿参加测试的145例研究对象, 根据eGFR值进行分组:1期[eGFR≥90 mL·(min·1.73 m2)-1, 37例]、2期[eGFR 60～90 mL·(min·1.73 m2)-1, 39例]、3期[eGFR 30～60 mL·(min·1.73 m2)-1, 47例]、4期[eGFR 15～30 mL·(min·1.73 m2)-1, 17例]、5期[eGFR <15 mL·(min·1.73 m2)-1, 5例], 所有研究对象通过静脉注射碘海醇5 mL后, 在注射后0、2 h和4～6 h间取血浆样本3次, 测量血浆清除率, 进行肾功能评估, 并与常用的肾功能评估公式[MDRD、内生肌酐清除率(Ccr)、CKD-EPI、Cockcroft-Gault]进行比较。结果 Ccr、MDRD公式计算eGFR值高于采用碘海醇血浆清除率计算的mGFR值(均P<0.05), 而Cockcroft-Gault、CKD-...     

肾小球滤过率下降与肾血管病变的相关性分析

长期高血压对肾血管具有重要的影响,但在不少肾脏疾病中,组织学检查显示有明显肾血管病变的患者而临床上并无高血压。为了明确肾血管病变除受血压等因素影响外,是否与肾脏功能的丢失有关,我们将两者进行了相关性分析。材料与方法1.病例:回顾性选择140例患者,除外原发性高血压、年龄超过50岁、糖尿病及吸烟患者。考虑到不同的原发病对肾血管病变的影响,故本组选择的病例均为肾活检示原发性IgA肾病患者。收集所有患者的临床资料,以MDRD简化公式评估肾小球滤过率(GFR),并按K/DOQI慢性肾脏疾病(CKD)的分期标准将IgA肾病分期。2.临床分组…     

三种肾小球滤过率检测方法与99mTc-DTPA清除率的比较与分析

目的为临床准确评估肾小球滤过率（GFR）提供一定依据。方法对101例各种慢性肾脏病患者,外周静脉注射非离子型造影剂碘海醇（iohexol）5ml,4h后取血2ml,用高效液相色谱（HPLC）法检测血浆iohexol浓度。运用数字模型计算血浆iohexol清除率（iohexol-GFR）。同步检测Scr及^99mTc—DTPA清除率（^99mTc—GFR）。应用Cockcroft—Gait（CG）、肾脏病膳食改良试验（MDRD）公式计算Ccr、GFR。以^99mTc—GFR为标准,运用相关回归分析及受试者工作曲线（ROC）对上述指标进行比较。结果慢性肾脏病第1期至第5期,iohexol—GFR与^99mTc-GFR相关系数r分别为0．87、0．89、0．88、0．86、0．87（P均〈0．01）;iohexol—GFR在ROC曲线下面积平均为0．97。MDRD—GFR与^99mTc—GFR相关系数r分别为0．80、0．75、0．71、0．67、0．56（P均〈0．01）,MDRD—GFR在ROC曲线下面积平均为0．82。CG—Ccr与^99mTc—GFR相关系数r分别为0．76、0．67、0．62、0．60、0．53（P均〈0．05）,CG—Ccr在ROC曲线下面积平均为0-82。结论iohexol—GFR检测GFR的准确性优于MDRD—GFR、CG—Ccr,值得推广应用。在无检测条件的情况下,CG、MDRD公式不失为衡量GFR的良好指标。     

肾小球滤过功能评估方法的研究进展及其评价

肾小球滤过功能是肾脏最重要的功能之一,用肾小球滤过率（ glomerular filtration rate,GFR ）表示。临床上准确评估GFR对于正确判断慢性肾脏病（ chronic kidney disease,CKD）分期,评估CKD进展速度,评价治疗效果,调整用药及判断开始肾脏替代治疗时机均有重要意义。但是GFR不能直接测定,只能用某种标志物的肾脏清除率或血浆清除率来推测。目前有多种方法评估GFR,但每种方法都是优点缺点共存。本文对几种肾小球滤过率评估方法做一综述,并进行初步评价。     

应用99mTc-DTPA摄取率测定肾小球滤过率与传统方法计算肌酐清除率的比较

目的评估在中国慢性肾脏病人中应用肌酐清除率(Ccr)估计肾小球滤过率(GFR)的有效性,并介绍由ToTo等人推导出的一条计算Cc r的新公式(我们简称ToToes'公式).方法研究中国慢性肾脏病人100例(男50例,女50例).应用99mTc-DTPA摄取法(Gates法)测定GFR;采用三种方法根据血肌酐(Scr)计算Cc r24 hCcr(24hCcr),Cockcroft-Gault公式计算Ccr(Cc r-CG)及用ToToes'公式计算Ccr(Ccr-TT);然后将Ccr与测定的GFR比较,其准确度用二者的差值(△GFR=GFR-Ccr)和比值(GFR ratio=Ccr/GFR)来评估,可靠性用决定系数r2和平方误差的联合平方根(CRMSE)来评估.结果男性组(1)△GFRCcr-CG≈CCR-T＜24 hCcr;(2)GFR ratioCcr-CG≈Ccr-TT＞24 hCcr;(3)r2Ccr-CG＞Ccr-TT＞24 hCcr;(4)CRMSECcr-CG≈Ccr-TT＜24 hCcr.女性组(1)△GFRCcr-TT＜Ccr-CG＜24 hCcr;(2)GFR ratioCcr-TT＞Ccr-CG＞24 hCcr;(3)x2Ccr-CG＞Ccr-CG≈24hCcr;(4)CRMSECcr-TT＜Ccr-CG＜24 hCcr.结论在三种方法中,ToToes'公式的准确度和可靠性在女性组明显高于目前常用的Cockcroft-Gault公式,男性组与Cockcroft-Gault公式相似;24hCcr明显低于前二者.     

应用^99mTc—DTPA清除率测定肾小球滤过率及与传统方法的比较研究

目的为临床准确评估ＧＦＲ提供一定依据。方法我们对３２例慢性肾脏病患者及５例正常志愿者，用９９ｍＴｃ－ＤＴＰＡ的清除率测定肾小球滤过率（Ｔｃ－ＧＦＲ），同时测定血尿素氮（ＢＵＮ），肌酐（Ｓｃｒ），２４小时肌酐清除率（２４ｈＣｃｒ）和采用Ｃｏｃｋｃｒｏｆｔ－Ｇａｕｌｔ公式计算肌酐清除率（Ｃｃｏｃｋｃｒｏｆｔ），并进行比较和分析。结果以上指标与Ｔｃ－ＧＦＲ均存在相关关系；它们检出Ｔｃ－ＧＦＲ下降的敏感性分别是５０％、５８％、６９％和８０％；２４ｈＣｃｒ和Ｃｃｏｃｋｃｒｏｆｔ与Ｔｃ－ＧＦＲ的相关性显著优于ＢＵＮ，Ｃｃｏｃｋｃｒｏｆｔ检出Ｔｃ－ＧＦＲ下降的敏感性显著优于ＢＵＮ。结论传统的指标除ＢＵＮ外均能一定程度地准确反映ＧＦＲ。９９ｍＴｃ－ＤＴＰＡ清除率可以准确，安全，有效地测定ＧＦＲ，适用于某些对ＧＦＲ精确性要求较高的情况。     

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。     

Measurements of glomerular filtration rate with iohexol plasma clearance: method selection and evaluation

Objective To compare the consistency between single-(I-GFR-SS) and dual- (I-GFR-DS) sample methods with three-sample method (I-GFR-TS) of iohexol plasma clearance in chronic kidney disease (CKD) patients for choosing the optimizing project of glomerular filtration rate (GFR) measurement. Methods The multiple-sample methods were performed in 174 patients with CKD admitted to the Department of Nephrology, Shanghai Ruijin Hospital from August 2017 to July 2018. Plasma concentrations of iohexol were measured three times at different time points after receiving 5 ml iohexol (300 g/L) intravenous injection, according to estimated GFR (eGFR) grouping. The first blood sample was collected at 2 hours, and the time for the last sample was delayed from 4 hours to 6 hours with reduction of eGFR. The synchronized Gates (99mTc-Gates-GFR) method was detected as control. With I-GFR-TS as the golden standard, the accuracies of I-GFR-DS, I-GFR-SS and 99mTc-Gates-GFR were compared. Results The median differences of I-GFR-DS, I-GFR-SS and 99mTc-Gates-GFR in overall patients were -0.15, -1.00, 6.76 ml?min-1?(1.73 m2)-1 comparing with I-GFR-TS; P10(percentage of the GFR measurements that was within 10% of the standard method) were 95.4%, 74.1%, 28.7%, and P30 were 100%, 93.7%, 72.4% separately. In the patients with eGFR＜30 ml?min-1?(1.73 m2)-1, I-GFR-SS was more accurate when last point collecting extended to 6 h from 4 h[P10: 43.5% vs 17.4%, P=0.055; P30: 73.9% vs 43.5%, P＜0.05]. Conclusions The dual-sample plasma clearance of iohexol is recommended in clinical practice, and the single-sample method can be a secondary option because of its slightly poor accuracy but more convenient. Sample-collection protocol should be adjusted according to eGFR especially in moderate-to-severe CKD patients. The Gates method is not recommended.     

Creatinine clearance following cimetidine for estimation of glomerular filtration rate

Simultaneous inulin (C _in) and creatinine clearance (C _Cr) studies were performed on 53 pediatric renal patients using a cimetidine protocol. Since cimetidine blocks the tubular secretion of creatinine, it was hypothesized that C _Cr measured following cimetidine would closely approximate the C _in. C _in was compared with C _Cr with the latter calculated from: (1) a 24-h urine collection, (2) plasma creatinine, height, and a proportionality constant, (3) the same plasma and urine specimens used for calculating C _in, and (4) from the plasma and urine specimens of the four 30-min clearance periods treated as a single 2-h clearance. The C _in was very closely approximated by the C _Cr calculated from the same specimens used for the C _in and by the 2-h clearance. The cimetidine protocol, with C _Cr derived from a 2-h urine collection obtained under supervision in the office or clinic, provides a convenient and inexpensive procedure for estimation of glomerular filtration rate in a clinical setting. Received January 21, 1997; received in revised form June 16, 1997; accepted June 20, 1997     

The measured glomerular filtration rate (mGFR) before and 6 months after bariatric surgery: A pilot study

IntroductionOver the last few decades, the prevalence of obesity has increased dramatically. This increase has been mirrored by a rise in the risk of a number of health conditions, including hypertension, diabetes and chronic kidney disease. Although the weight loss following bariatric surgery has been shown to relieve the severity of diabetes and reduce hypertension, the effect on renal function has been less extensively evaluated.ObjectiveThe aims of the present study were to: (i) compare the estimated glomerular filtration rate (eGFR, using the MDRD and CKD-EPI equations) and the calculated glomerular filtration rate (using the 24-hour urine volume) with the measured glomerular filtration rate (mGFR) assessed with the plasma iohexol clearance method in severely obese patients, and (ii) evaluate the effect of weight loss on the mGFR 6 months after bariatric surgery.MethodsBefore and six months after bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy), eligible patients for bariatric surgery were admitted as day cases to the nephrology unit, where they underwent a plasma iohexol clearance test. The GFR was also estimated using the MDRD and CKDEPI equations and the 24-hour urine method. Changes in eGFR and mGFR were compared using a Wilcoxon test for paired data.ResultsData from 16 patients with severe obesity (mean ± standard deviation of Body Mass Index [BMI]: 43.9 ± 7.3 kg/m²) were analyzed. At baseline, 12 (75%) presented with hypertension and 10 (63%) presented with diabetes. The median [range] iohexol clearance rate was 109 [57–194] mL/min. The plasma iohexol clearance test evidenced hyperfiltration (mGFR > 120 mL/min) in 7 patients. In contrast, the eGFR values generated by the MDRD equation, the CKDEPI equation and the GFR MFR calculated with the 24-hour urine method only identified hyperfiltration in 1, 0 and 5 patients, respectively. Six months after surgery, the mean BMI had fallen significantly (P < 0.0012), and the severity of diabetes (according to the HbA_1c level) had decreased significantly from 6.6 [6.0–9.8] % to 5.7 [5.2–8.6] % (P = 0.025). The iohexol clearance rate increased slightly after bariatric surgery. Changes in BMI after surgery do not seem to be correlated with the changes in iohexol clearance. In patients displaying hyperfiltration at baseline, the mGFR fell significantly (n = 7; P = 0.01) and returned to near normal values. No significant changes in the eGFR were observed.ConclusionOur results suggest that MDRD and CKD-EPI equations do not provide accurate estimates of the true GFR in severely obese patients (particularly in those with hyperfiltration). Iohexol clearance or other methods for determining mGFR should constitute the gold standard for the accurate evaluation of renal function in this context. Renal function (as evaluated by the mGFR) improved 6 months after bariatric surgery in severely obese individuals particularly in patients displaying hyperfiltration at baseline. However, these observations must be confirmed in a larger study with a longer follow-up period.     

Expressing glomerular filtration rate in children

We have reviewed the studies that provide the current standards of reference for glomerular filtration rate (GFR) in normal children from 14 days to 12 years of postnatal age. These standards currently are presented as ml/min per 1.73 m², i.e., adjusted to average adult body surface area. Children from birth to 1 year of age have adjusted values below the adult range, making comparisons of observed to reference values difficult. Currently, there is no accepted way of obtaining reference values that vary smoothly with age. An analysis of the absolute GFR values in normal children taken from published studies led to an equation that estimates average GFR in relation to weight and term-adjusted age from-2 months (7 months gestational age) to 12 years in children at least 14 days post delivery. When these data are transformed to percentage of normal (% nl) for age and weight (i.e., percentage of the estimated average), it is possible to describe approximate apparent lower limits of normal GFR as is now done for adults and older children. For children with loss of renal mass, GFR expressed as % nl for age and weight provides a convenient standardization which has several useful applications. First, results expressed as % nl for children of different ages, particularly under 1 year of age, can be combined with those of older children for summary purposes. Second, the course of GFR measured serially in children is more appropriately described using this method for expressing GFR. Reporting GFR in absolute values is also useful, particularly in patients whose body mass is significantly distorted or whose absolute GFR is low.     

Inaccuracy of estimated creatinine clearance for prediction of iothalamate glomerular filtration rate

The clinical practice of estimating creatinine clearance (Ccr) from a patient's serum creatinine value by use of various nomograms and prediction formulas is widespread. The predictive accuracy of such Ccr estimates as substitutes for measured values of glomerular filtration rate (GFR) has not been determined. In addition, the effect of patient physical parameters on GFR prediction accuracy has not been assessed. To investigate these issues, 500 predicted Ccr values from each of four versions of the formula of Cockcroft and Gault were statistically compared with GFR values measured by sodium iothalamate clearance (Cio) in 394 human subjects representing every level of renal function. We conclude that (1) the original formula of Cockcroft and Gault is an inaccurate predictor of GFR; (2) correction of the formula for patient physical parameters does improve its accuracy for GFR prediction; (3) the best formula is not accurate enough to replace laboratory measurement of GFR; and (4) GFR prediction inaccuracy is more often associated with extremes in patient age, weight, serum creatinine, body surface area, and measured GFR but may occur for any value of each of these parameters.     

Estimating absolute glomerular filtration rate in children

Normal values of glomerular filtration rate (GFR) in children are often expressed in a value adjusted to adult ideal body surface area. These values work well for many clinical situations, but in infants and children, especially those with atypical body mass, they may not accurately reflect renal function. Most body composition values in children are expressed in developmentally appropriate ranges. Absolute GFR (ml/min) also changes during childhood increasing rapidly in infancy and then gradually with age and body size. Previously, we developed a bedside equation for estimating GFR (ml/min) in children that accounted for changes with age and body size, and which correlated well with steady-state cold iothalamate GFR (ml/min) measurements: GFR (ml/min) = k_*sqrt[(age(months) + 6)*wt (kg)/serum Cr (mg/dl)], where k=0.95 for females and 1.05 for males. In the present study GFR (ml/min) measured by iothalamate infusion was compared by correlation analysis with estimates calculated from the above equation in 566 children. This equation provides clinicians with a simple bedside method to estimate absolute GFR (ml/min).     

不同公式估算慢性肾脏病患者肾小球滤过率的结果评价

目的探讨不同估算公式估算慢性肾脏病（CKD）患者肾小球滤过率（GFR）在肾功能评价中的价值。方法选择CKD患者239例,所有患者同步检测99锝-二乙烯三胺五乙酸（^99mTc-DTPA）、GFR、血肌酐（SCr）等。将^99mTc-DTPA测定的GFR作为参照,并用肾脏病膳食改良试验（MDRD）公式、Cockcroft-Gault公式、简化MDRD公式及慢性肾脏病流行病合作研究（cKD-EPI）公式计算估测GFR,比较不同CKD分期中各估算公式估算的GFR的准确性。结果各估算公式估算的GFR值均高于^99mTc-DTPA,MDRD公式偏离程度最大;各估算公式估算的GFR值与^99mTc-DTPA检查的GFR结果有相关性,CKD-EPI公式相关性最高。结论CKD-EPI公式估算肾功能更接近^99mTc-DTPA的结果,但仍需进一步校正。     

Creatinine for estimation of glomerular filtration rate

The aim of this study was to evaluate the plasma creatinine concentration (P_Cr) and creatinine clearance (C _Cr) for estimation of glomerular filtration rate (GFR). Inulin clearance (C _in) was used as the reference standard for GFR. Thirty-nine concurrentC _in andC _Cr studies provided data for comparingC _in with the measuredC _Cr and with the calculatedC _Cr (calc-C _Cr). (Calc-C _Cr=k·L/P_Cr, where L=height in centimeters and k is the proportionality constant.) Thirty-one children 5.3–20.8 years of age, withC _in ranging from 2.8 to 138.8 ml/min per 1.73 m², participated in these studies at The Children's Mercy Hosptial. The measuredC _Cr was 16.7±10.3 ml/min per 1.73 m² (P<0.001) greater than theC _in, and the calc-C _Cr overestimatedC _in by a mean of 31.6±20.8 ml/min per 1.73 m² (P<0.001). Although there is good correlation betweenC _in andC _Cr (r=0.96), andC _in and calc-C _Cr (r=0.90), the 95% confidence intervals are quite broad. Hence, theC _Cr and the calc-C _Cr, derived using Schwartz values for k, consistently overestimate GFR. However, if the k value in the equation GFR=k·L/P_Cr is derived from k=C _in/L, rather than from k=C _Cr·P_Cr/L, a more accurate estimate of GFR may be obtained.