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Background: Estimated glomerular filtration rate (eGFR) has always been considered a better and more accurate method to assess kidney function as compared to serum creatinine. Various equations such as the Cockroft-Gault equation corrected for surface area (CG-CRTD), the four-variable Modification of Diet in Renal Disease equation (MDRD) and 2009 Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) have been derived to estimate GFR. In the South Asian region, the CKD-EPI equation has not been validated or compared with other equations. This study compares eGFR in a Pakistani community cohort calculated by all three equations. Results: Serum creatinine was measured using Kinetic Colorimetric Assay in alkaline medium for 461 individuals age 15 and above. Less than half of the participants (47% by CG-CRTD, 40% by MDRD, 52% by CKD-EPI) had eGFR ³90 ml/min per 1.73 m2 and for participants with eGFR ³120 ml/min per 1.73 m2 , the percentages were even lower (15%, 12%, and 22% respectively). All the equations were linearly associated with each other, but the error estimation depicted that majority of the individual differences were ≥5 and ≤-5, and very few were within ±1 indicating less degree of agreement between the formulas. Age was significantly but negatively correlated with all the three formulas in their classification of patients as per eGFR Conclusion: Our study found that the values of estimated GFR are on lower side for Pakistanis as compared to the western population. The equations available for estimation of GFR even though associated linearly with each other have significant individual differences. Thirdly, using eGFR to classify CKD should have a better consideration of physiological age-related decline in GFR. All of these findings necessitate having an adequately funded randomized study measuring true GFR of this population and at the same time validating eGFR equations to find the normal GFR ranges of South Asians.

Leptospirosis is a frequent zoonosis in the tropics including Indonesia with 5–30% incidence and 5–20% mortality rate due toacute renal failure (ARF). To determine the frequency of leptospirosis by sex, age and glomerulus's filtration rate (GFR) of the patient.A retrospective descriptive study on 32 subjects was done by measuring the creatinine clearance using Lyasis Auto analyzer in ClinicalPathology Laboratory of Wahidin Sudirohusodo Hospital from January 2004 to June 2006, of 32 patients, 25 (78%) male and 7 (22%)female, with the most frequent age range from 30–40 years (34.4%). Of the patients, 2 (6.3%) have normal GFR, 6 (18.8%) withmild GFR reduction, 10 (31.3%) with medium GFR reduction, 10 (31.3%) with severe GFR reduction and 4 (12.5%) with acute renalfailure. Leptospirosis is most frequent found in male with age between 30–40 years old. with reduction of GFR from mild to severe, andeven terminated with acute renal failure.

The prevalence of chronic kidney disease (CKD) clearly depends on its definition, and the definition used most often is the one proposed by the Kidney Disease: Improving Global Outcomes guidelines in 2012: 'CKD is defined as abnormalities of kidney structure or function, present for3 months, with implications for health.' Abnormality of kidney function is a glomerular filtration rate (GFR)60 mL/min/1.73 m2, and the most frequently used marker of kidney damage is the presence of albuminuria [albumin excretion rate 30 mg/24 h or albumin/creatinine ratio (ACR)30 mg/g (or 3 mg/mmol)]. However, two major aspects of this definition could explain why CKD prevalence is, in our view, overstated in most epidemiological studies. First, the fixed threshold at 60 mL/min/1.73 m2 is questionable because normal GFR decreases with age. This and the profound consequence it has on CKD epidemiology will be illustrated. The second aspect of the definition is the criterion of chronicity, which is ignored by the vast majority of epidemiological studies. In other words, confirming CKD (low GFR and/or high ACR) is mandatory. Indeed, a large proportion of subjects with a low first GFR level has a normal GFR level when tested a second time. The prevalence of CKD may hence, in fact, be considerably lower although still neither negligible nor irrelevant.

Aims Influx and reabsorption of phosphorus (IP and TRP) are assessed with fractional excretion and reabsorption (FEP and FTRP, nl ≤ 20% and ≥ 80%), or with excretion and reabsorption per volume of filtrate (EP/GFR and TRP/GFR, fasting nl ≈ 0.4 and 3.0 mg/dL). We analyzed these parameters at normal and reduced GFR. Methods We equated GFR with creatinine clearance (Ccr) to develop necessary equations. We plotted serum phosphorus ([P]s), EP/Ccr, and FEP against their determinants, and TRP/Ccr against EP/Ccr at FEP of 20% or 40%. Results Linear equations related [P]s to EP/Ccr and TRP/Ccr, and EP/Ccr to [cr]s and [P]u/[cr]u (a surrogate for IP). FEP rose in curvilinear fashion as Esub>P/Ccr rose and TRP/Ccr fell; changes in low values of EP/Ccr and TRP/Ccr induced large changes in FEP. At increased EP/Ccr (as in CKD), maintenance of FEP ≤ 20% required impossibly high TRP/Ccr; at EP/Ccr of 2.0 mg/dL, FEP and FTRP of 40% and 60% required normal TRP/Ccr. Conclusions EP/Ccr varies with IP at normal GFR, and with IP and [cr]s at low GFR. FEP, a function of EP/Ccr and TRP/Ccr, varies primarily with the lower ratio, which is always EP/Ccr at normal GFR. At low GFR, high FEP is inevitable if IP is preserved, and TRP/Ccr may be normal despite low FTRP. Contributions of IP and TRP to [P]s should be assessed with EP/Ccr and TRP/Ccr. FEP and FTRP have limitations at any GFR.

BACKGROUND: Guidelines for measuring glomerular filtration rate (GFR) using Cr-EDTA require normalizing of GFR for body surface area (BSA) before applying the Bröchner-Mortensen (BM) correction. The guideline explicitly mentions the importance of performing BSA normalization before BM correction and that this is particularly important in children in whom the effects of BSA normalization are largest. MATERIALS AND METHODS: We theoretically showed that the order of applying BM correction and BSA indexing is indeed important for patient populations having a low BSA and a high slow GFR. We then compared the exact GFR, obtained from the double-exponential concentration-time curve in Duchenne muscular dystrophy (DMD) patients, with the GFR obtained from the slow compartment method using the BM correction. RESULTS: The median GFR for the 20 DMD patients obtained from the BSA-BM order deviates 5.40% from the exact GFR (P=0.0006), whereas the median GFR obtained from the BM-BSA order deviates only -0.05% (P>0.05) from the exact GFR, resulting in a median of differences of 5.50% between the two methods (P

The current glomerular filtration rate (GFR) equation (CKiD) may be less accurate in adolescents and children with higher GFR. This was a retrospective study (n = 161, 247 99mTc DTPA-GFRs). Six equations were evaluated for bias, accuracy, and low GFR diagnosis: (1) CKiD; (2) historic center; (3) Hoste(age); (4) Hoste(height); (5) modified Pottel; (6) Gao. Children with ≥ vs.

Determining true glomerular filtration rate (GFR) using an exogenous marker is time-consuming and cumbersome. Therefore, creatinine-based estimates of GFR are used. Recent papers using new population-specific/local parameters in their prediction equations, standardizing creatinine determination or adding other endogenous surrogate markers of GFR, like cystatin C, could demonstrate an improvement of bias inherent in the results of the prediction equations. Precision, however, is still poor. Currently, we have to accept a precision (as defined in the so-called Bland-Altman plot) of +/-20% in adults and +/-30-40% in children. This problem of poor precision/uncertainty is especially bothering in the higher, near normal GFR range. Caution should be exercised when applying prediction equations in individuals in need of an accurate GFR determination. In that case, a real clearance procedure has to be performed. In the long run, the true clearance procedure should be simplified using new exogenous GFR markers and developing new devices, allowing GFR measurements to be performed, for example, transcutaneously. Such a procedure would be more acceptable for both patients and physicians.

Dogs have provided classic models of induced hypertension. This paper shows that despite being susceptible to hypertension, they are naturally resistant to its development even when renal function is severely compromised. The proportion of hypertensive dogs was almost as low among those with reduced glomerular filtration rate (GFR) (9%) as those with normal GFR (6%). Dogs with GFR less than 33% of the normal lower limit (with an average GFR equivalent to 10 mL min-1 in a 70-kg patient) had arterial pressures not significantly above normal. Only dogs with a GFR 33-75% of the lower limit of normal had significantly elevated systolic pressure, though none was actually hypertensive. Since there was no correlation between arterial pressure and GFR below 33% of lower limit, the dogs in the 33-75% range may be showing an effect of increased pressure, rather than a cause. In humans with GFR less than 33% of normal, the majority are hypertensive. Since various aspects of canine cardiovascular and renal function are comparable with humans, the question is why dogs, despite being capable of developing hypertension, are resistant to it, even when they have chronic renal insufficiency.

In nephrology, chronic kidney disease is defined by both proteinuria and measurement of glomerular filtration rate (GFR). This article focuses on GFR and different ways to define its normal reference values. In this context, we compare two perspectives: first the reference values defined by measuring GFR in normal individuals (the ‘classical way’) and secondly a fixed cut-off value at 60 mL/min/ 1.73 m 2 according to the associated mortality risk (the ‘prognostic way’). Following the classical way, we can assert that normal GFR values are largely over 60 mL/min/ 1.73 m 2 in healthy subjects, at least before the age of 70 years. However, we know that GFR physiologically decreases with age, and in adults older than 70 years, values below 60 mL/min/1.73 m 2 could be considered normal. Following the ‘prognostic way’ ,t hefixed cut-off of 60 mL/min/1.73 m 2 has been retained in the K-DIGO guidelines. However, we challenge this concept and the fact that the variable ‘age’ is poorly taken into account in these data. There is an obvious discrepancy between the reference values defined either by the ‘classical way’ or by the ‘prognostic way’ which we think could be largely reduced, if age was better taken into consideration in these definitions.

Udgivelsesdato: 2010-Feb BACKGROUND: Previously, data on both the within-subject (SD(I)) and the between-subject (SD(G)) variation of cystatin C in children has not been reported. Thus, this study aimed to determine this biological variation including analytical variation (SD(A)) of both cystatin C and creatinine to characterize the two analytes as renal function markers in children. METHODS: On two consecutive days blood samples for duplicate analysis of cystatin C (nephelometric, Dade Behring) and creatinine (enzymatic, Roche) were obtained from 30 children (11 females and 19 males, mean age 8.3 range 2-13 years) referred for GFR measurements by (51)Cr-EDTA clearance. For determination of the between-subject variation only children with normal GFR (n=21) were included. Data were adjusted for the well known age-related increase in creatinine. RESULTS: The results are given as coefficients of variation. The within-subject variations were identical for both analytes (6.4%). The between-subject variation was 11.1% for cystatin C and 28.4% for creatinine, though decreasing to 20.1% after adjusting for age. The analytical variation was 1.7% and 2.5% for cystatin C and creatinine, respectively. The index of individuality (IOI = SD(I)/SD(G)) was 0.65 for cystatin C and 0.25 for creatinine, though increasing to 0.36 after age-adjustment. CONCLUSION: The within-subject variation was identical and low for cystatin C and creatinine suggesting that the two are equally suitable for serial monitoring of renal function in children. Based on the low IOI neither analyte, however, seems suitable as a screening marker of renal function in a healthy population of children using population-based reference intervals.

Background Prevalence of stage 3 chronic kidney disease (CKD) is increasing according to the NHANES study. Prevalence has been calculated using the MDRD study equation for estimating glomerular filtration rate (GFR). Recently, a new estimator based on creatinine, the CKD-EPI equation, has been proposed which is presumed to better perform in normal GFR ranges. The aim of the study was to measure the difference in prevalence of stage 3 CKD in a population using either the MDRD or the CKD-EPI study equations. Methods CKD screening is organized in the Province of Liège, Belgium. On a voluntary basis, people aged between 45 and 75 years are invited to be screened. GFR is estimated by the MDRD study equation and by the "new" CKD-EPI equations. Results The population screened consisted in 1992 people (47% of men). Mean serum creatinine was 0.86 ± 0.20 mg/dL. The prevalence of stage 3 CKD in this population using the MDRD or the CKD-EPI equations was 11.04 and 7.98%, respectively. The prevalence of stage 3 CKD is significantly higher with the MDRD study equation (p < 0,0012). Conclusions Prevalence of stage 3 CKD varies strongly following the method used for estimating GFR, MDRD or CKD-EPI study equations. Such discrepancies are of importance and must be confirmed and explained by additional studies using GFR measured with a reference method.

The result of a glomerular filtration rate (GFR) measurement on a particular patient is of limited use to the referring physician since normal GFR values vary widely with the patient's age and build, etc. To overcome this problem, it is usual to normalise the measured GFR by dividing it by the patient's surface area and multiplying the result by the surface area of a 'standard' man. This transforms the measurement onto a scale which applies to all patients, young and old, large and small, where normal values fall within a well-defined range and where the degree of renal impairment can be quantified. We have examined the generally accepted surface area (SA) and the less well-known extracellular volume (ECV) normalisation methods of GFR measurements in a series of 110 patients. The results show that both methods produce essentially the same result; however, ECV normalisation is theoretically more correct, can be found directly without the patient's ECV being measured and does not require the use of empirical formulae. Mathematical justification for ECV normalisation is presented, and a proposed distribution pattern for the normalised measurement is introduced. A simple mathematical model shows that accurate GFR measurements can be made in the presence of an enlarged ECV, but normalisation of these will produce misleading low values.

Background. Although recommended, both theCockcroft and Gault formula (CG) and the modifica-tion of diet in renal disease (MDRD) equation arenot ideally predictive of glomerular filtration rate(GFR) in diabetic subjects; we tested whether the newMayo Clinic Quadratic (MCQ) equation performedbetter.Methods. In 200 diabetic subjects with a wide range ofrenal function, GFR was measured by 51Cr-EDTAclearance, and compared with the results of the threepredictive equations by regression analysis and Blandand Altman procedures. The correlations with bodymass index, age and albumin excretion rates weretested. The precisions (absolute difference as percent-age), diagnostic accuracies [receiver operating char-acteristic (ROC) curves for the diagnosis of moderateand severe chronic kidney disease (CKD)], and theresults of stratification according to the KDOQclassification were compared.Results. The CG and MCQ overestimated mean GFR,whereas the MDRD underestimated it. CorrelationcoefficientsandareasundertheROCcurveswerebetterfortheMDRDandtheMCQascomparedwiththeCG,which was biased by body weight (þ30% overestima-tioninobesediabeticsubjects).Theabsolutedifferenceswith true GFR were slightly lower for the MDRDthan the MCQ, and both better than the CG. Boththe MDRD and MCQ correctly stratified 65% of thesubjects (CG: 55%, P

We have studied the incidence and the clinical significance of high glomerular filtration rate(HGFR) that can appear in some patients after renal transplantation.From 234 functioning renal transplants 17% of them presented HGFR even on Cyclosporine therapy.The only difference with patients with normal GFR was that HGFR patients showed a better Creatinine Clearance at the end of first posttransplant month and patients on Cyclosporine exhibited a shorter renal function recovery time. Now, the clinical significance of HGFR are unknown.

2These prevalence data are thus not easy to compare with those of the US population, for which the newly expressed Modification of Diet in Renal Disease (MDRD) study equation 3 was used. This equation is applied to standardised creatinine with a factor of 175; Wen and colleagues used the version of the equation with a factor of 186. 3 and Japanese 4 populations, correction factors of 1.21 and 0.763, respectively, must be applied. Such a correction was not done by Wen and colleagues and should be discussed. Lastly, Wen and colleagues showthat nearly one in three patients older than 65 years presented with stage 3 CKD. The term "disease" in this age group is debatable because the normal GFR in older populations is not well defined; a GFR of less than 60 mL/min/1 ·73 m 2 could be regarded as physiological in a healthy older person. 5

SUMMARY Two groups of patients receiving cyclosporin A (CyA) for psoriasis had their renal function assessed by measurement of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). The first group comprised 13 patients who had taken low dose (average 3 mg/kg per day) CyA for an average period of 25 years. Seven of the 13 had a normal GFR of 108 (77–121) ml/min (median; range). In the other six patients the GFR was low at 63 (50–77) ml/min and CyA was discontinued for periods ranging from 3 to 17 weeks. The GFR rose in all six patients, to 79 (60–91) ml/min; this change was significant (P

A few days after ingestion of 40 match heads, a 3-year-old boy was admitted to hospital with oliguric acute renal failure (ARF) requiring peritoneal dialysis during 9 days. A renal biopsy showed acute tubulointerstitial nephritis; the outcome was rapidly favorable and the child recovered normal GFR. It seems to be the first published case of ARF after match poisoning, probably because of the presence of potassium bichromate.

In 28 patients with bilaterally recurring calcium – containing renal staghorn calculi, 14 with normal GFR and 14 with mild renal insufficiency, a metabolic investigation of calcium metabolism during i

Glomerular response mechanisms to glycemie changes in insulin-dependent diabetics. Glomerular filtration rate (GFR) and renal plasma flow (RPF) were measured by constant inulin and PAH infusion during euglycemia and intravenous dextrose-induced moderate hyperglycemia in seven insulin-dependent diabetics with persistently elevated GFR, seven diabetics with normal GFR, and in six normal control subjects. In euglycemia, RPF was higher and calculated renal vascular resistance (RVR) lower in the hyperfiltering than the normofiltering group (P < 0.05 for both variables), but filtration fraction (FF) was similar in all groups. During hyperglycemia, mean GFR rose significantly from 157 ± 20 to 174 ± 30 ml/min/1.73m2 (11.9%; P < 0.05) in the hyperfiltering group only. There was no statistically significant change in mean GFR in the normofiltering diabetic (116 ± 6 vs. 114 ± 13 ml/min/1.73m2) and the normal control groups (117 ± 15 vs. 113 ± 14 ml/min/1.73m2). RPF and FF rose by 5.8% and 9.2%, respectively, in the hyperfiltering group only, with no change in the normofiltering or normal control groups. No change in RVR was found in any group. Total tubular sodium reabsorption was higher during euglycemia in the hyperfiltering diabetics (P < 0.01), and rose significantly during hyperglycemia (P < 0.05) in this group only. Overnight euglycemia did not remove the increased glomerular filtration and flow of hyperfiltering diabetics. Hyperglycemia further accentuated hyperfiltration by elevating renal plasma flow and filtration fraction.

The renal images recorded during 1 to 2 1/2 min postinjection in 99Tcm-DTPA gamma camera renography were used for determination of the total cleared renal fraction (TCRF) of cardiac output with respect to the radioactive indicator. The left and right cleared renal fractions of cardiac output were determined directly, i.e., assessment of single-kidney uptake function within a few minutes postinjection was also possible. TCRF was proportional to the glomerular filtration rate (GFR) determined by the 51Cr-EDTA plasma clearance in a group of 23 subjects with GFR in the interval 15 to 130 ml/min/1.73 m2. The slope of the regression line of TCRF against GFR was in agreement with the theoretical estimate for it. GFR could be predicted from TCRF with a standard error of estimate from 4 to 15 ml/min/1.73 m2 for values of GFR in the above interval. Intra-observer variability of TCRF was unbiased and varied between 4% (normal GFR) and 9% (decreased GFR). TCRF is proposed to represent an alternative to renal clearance for evaluation of renal uptake function.

Although plasma CL levels in NS have been found to be low or normal, their interpretation remains ambiguous. To evaluate plasma CL in relation to its regulatory factors during both relapse (RL) and remission (RM), chi tdren with NS and normal GFR were studied. Data were compiled in 58 patients (39 males, 19 females) ages 2 to 20 yr (x 10.1) during 79 RL and 82 RM, Results were: While, as expec+ed, in RM Ca correlated inversely (r = -0.04) and PTH directly (r = 0.12) with CL, in RL these correlations were direct (r = 0.48, p . We conclude that in nephrotic children, important abnormalities of mineral metabolism present in RL normalize during RM, daily protelnuria has a greater effect on plasma CD than on CL, and that circulating CL is normal in RL. The latter, however, is inappropriately low for the prevailing hypocalcemla and suggests inadequate synthesis of CL by the nephrotic kidney even with normal GFR.