Evaluation of Renal Function During Childhood

1996 ◽  
Vol 17 (5) ◽  
pp. 175-180
Author(s):  
Bassam A. Atiyeh ◽  
Shermine S. Dabbagh ◽  
Alan B. Gruskin
Keyword(s):  
Renal Function ◽  
Serum Creatinine ◽  
Neonatal Period ◽  
Urinary Concentration ◽  
Urine Collection ◽  
Limited Capacity ◽  
Urea Clearance ◽  
Schwartz Formula ◽  
Creatinine Concentration ◽  
Plasma Creatinine Concentration

There are several methods to evaluate renal function during childhood. The use of serum creatinine, either alone or in combination with the Schwartz formula, is reliable and quick, but requires knowledge of conceptual age. A plasma creatinine concentration of 88.4 µmol/L (1.0 mg/dL), for example, represents normal renal function in an adolescent but more than 50% loss of renal function in a 5-year-old child. A timed urine collection for creatinine clearance is another evaluative method, but the adequacy of the urine collection always should be determined first. Urea clearance rarely is used to measure GFR because of the complex factors that influence urea excreation. Measurement of the disappearance of radioactive-labeled substances in plasma can be used to determine GFR. Radionuclide renal scans also can be used and offer the advantage of estimating the GFR of each kidney. Although infants and newborns have an intact urine diluting ability, their concentrating ability is impaired. The maximal urinary concentration in the neonatal period is less than 700 mOsm/kg, but reaches adult values of 1200 mOsm/kg by 6 to 12 months of life. Similarly, the infant kidney has a limited capacity for salt regulation, predisposing the infant to salt disturbances.

Urinary Beta-Thromboglobulin Correlates with Impairment of Renal Function in Patients with Diabetic Nephropathy

1986 ◽  
Vol 56 (02) ◽  
pp. 229-231 ◽  
Author(s):  
A H Hopper ◽  
H Tindall ◽  
J A Davies
Keyword(s):  
Renal Function ◽  
Diabetic Nephropathy ◽  
Microvascular Disease ◽  
Normal Subjects ◽  
Specific Protein ◽  
Creatinine Concentration ◽  
Β2 Microglobulin ◽  
Plasma Creatinine Concentration ◽  
Insulin Dependent ◽  
Indium 111

SummaryTBeta-thromboglobulin (βTG) is a platelet-specific protein and since its concentration in plasma rises when platelets are activated, it has been used as an indicator of platelet involvement in vascular disease. Since platelets might be involved in the pathogenesis of diabetic microvascular disease we measured urinary βTG in 20 insulin-dependent diabetics with nephropathy and compared the results with those from 20 normal subjects. Measurement of βTG in urine was undertaken to avoid errors induced by blood sampling and to gain information over a prolonged period using a single assay. Measurements were made of βTG, β2-microglobulin and total protein in urine collected for 24 h and creatinine and β2 microglobulin in plasma. Survival of indium-111-labelled platelets was measured in nine patients. Urinary PTG was significantly (p <0.02) increased in the 20 patients compared with 20 normal volunteers (median value 1.3 vs 0.8 μg/24 h). There was a strong correlation between urinary βTG excretion and plasma creatinine concentration (r = 0.8, p <0.0001) and plasma β2-microglobulin concentration (r = 0.9, p <0.0001). Urinary βTG concentration did not correlate with platelet survival. The results indicate that although urinary βTG is significantly increased in patients with diabetic nephropathy its concentration in urine correlates with indicators of glomerular filtration rather than with a test of platelet activation.

Assessment of renal function

2015 ◽  
Author(s):  
Marijn Speeckaert ◽  
Jopis Delanghe
Keyword(s):  
Serum Creatinine ◽  
Creatinine Clearance ◽  
Clinical Decision Making ◽  
Clinical Decision ◽  
Estimation Methods ◽  
Renal Diseases ◽  
Accurate Estimation ◽  
Routine Practice ◽  
Schwartz Formula ◽  
Creatinine Concentration

Glomerular filtration rate (GFR) can be measured as the clearance of exogenous or endogenous filtration markers. Practical formulas permit estimation of creatinine clearance or GFR without timed urine collections in many stable patients with CKD. Standardization of serum creatinine is important for all of these estimation methods and implementing traceability of the assays to the new global SRM 967 standard has led to changes in clinical decision-making criteria. Calibration to an IDMS reference produces a lowering of serum creatinine values by 10–30% for most methods. Serum creatinine concentration depends on age, gender and muscle mass. Cystatin C is an alternative marker of GFR, but estimation is more expensive and it is not clear that it has a useful place in routine practice. The MDRD Study equation was validated in the framework of the Modification of Diet in Renal Diseases study. It is superior to the Cockcroft and Gault formula for estimating Creatinine Clearance in most people. In 2009, the CKD Epidemiology Collaboration (CKD-EPI) formula was introduced, which provides a more accurate estimation for patients with GFR values between 60 and 90 mL/min. In children, the Schwartz formula is frequently used. Some urinary markers of kidney disease are also discussed.

Kidney protection by pretreatment with free radical scavengers and allopurinol: Renal function at recirculation after warm ischaemia in rabbits

1986 ◽  
Vol 71 (3) ◽  
pp. 245-251 ◽  
Author(s):  
R. Hansson ◽  
S. Johansson ◽  
O. Jonsson ◽  
S. Pettersson ◽  
T. Scherstén ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Renal Function ◽  
Serum Creatinine ◽  
Kidney Tissue ◽  
Urine Osmolality ◽  
Free Radical Scavengers ◽  
Control Group ◽  
Creatinine Concentration ◽  
Pronounced Increase ◽  
Before And After

1. Renal function and morphology were studied before and after 60 min of renal ischaemia and contralateral nephrectomy in five groups of rabbits. The animals were pretreated with superoxide dismutase, catalase, allopurinol or mannitol. One group was not pretreated and served as a control. 2. A moderate transient increase in serum creatinine concentration was observed in the control rabbits, while a significantly less pronounced increase was noted after pretreatment with superoxide dismutase, catalase and mannitol. 3. Pretreatment with allopurinol did not significantly reduce the postoperative increase in serum creatinine and sodium excretion, but the urine osmolality returned to normal more rapidly than in the control group. 4. The appearance under the light microscope of kidney tissue taken from surviving rabbits was found to be normal irrespective of pretreatment. Severe tubular necrosis was observed in the kidneys from rabbits that died during the observation period.

scholarly journals Repeated measurements of renal function in evaluating its decline in cats

2018 ◽  
Vol 20 (12) ◽  
pp. 1144-1148 ◽  
Author(s):  
Natalie C Finch ◽  
Harriet M Syme ◽  
Jonathan Elliott
Keyword(s):  
Renal Function ◽  
Individual Variability ◽  
Repeated Measurements ◽  
Rate Of Change ◽  
Population Variability ◽  
Urine Specific Gravity ◽  
Creatinine Concentration ◽  
Plasma Creatinine Concentration ◽  
Positive Rate ◽  
Time Point

Objectives The aim of this study was to describe the variability in renal function markers in non-azotaemic and azotaemic cats, and also the rate of change in the markers. Methods Plasma creatinine concentration and its reciprocal, glomerular filtration rate (GFR) and urine specific gravity (USG) were studied as markers of renal function in client-owned cats. GFR was determined using a corrected slope-intercept iohexol clearance method. Renal function testing was performed at baseline and a second time point. The within-population variability (coefficient of variation; CV%) was determined at the baseline time point. Within-individual variability (CV%) and rate of change over time were determined from the repeated measurements. Results Twenty-nine cats were included in the study, of which five had azotaemic chronic kidney disease. The within-individual variability (CV%) in creatinine concentration was lower in azotaemic cats than in non-azotaemic cats (6.81% vs 8.82%), whereas the within-individual variability in GFR was higher in azotaemic cats (28.94% vs 19.98%). The within-population variability was greatest for USG (67.86% in azotaemic cats and 38.00% in non-azotaemic cats). There was a negative rate of change in creatinine concentration in azotaemic and non-azotaemic cats (–0.0265 and –0.0344 µmol/l/day, respectively) and a positive rate of change of GFR in azotaemic and non-azotaemic cats (0.0062 and 0.0028 ml/min/day, respectively). Conclusions and relevance The within-individual variability data suggest creatinine concentration to be the more useful marker for serial monitoring of renal function in azotaemic cats. In contrast, in non-azotaemic cats, GFR is a more useful marker for serial monitoring of renal function. The majority of cats with azotaemic CKD did not have an appreciable decline in renal function during the study.

Renal function in water snakes

1962 ◽  
Vol 203 (6) ◽  
pp. 995-1000 ◽  
Author(s):  
S. J. LeBrie ◽  
I. D. W. Sutherland
Keyword(s):  
Tubular Secretion ◽  
Urine Flow ◽  
Urinary Concentration ◽  
Clearance Ratio ◽  
Creatinine Concentration ◽  
Plasma Creatinine Concentration ◽  
Tenfold Increase ◽  
Solute Excretion ◽  
Water Snakes ◽  
Filtered Load

Electrolyte and osmolar concentrations of ureteral urine were compared with serum in several species of water snakes. Hyperosmotic urine was never observed, even after 48 hr of water deprivation. This finding is consistent with the countercurrent theory which precludes urinary concentration when Henle's loops are absent, as in reptilian kidneys. The creatinine/inulin clearance ratio may exceed 2.0, suggesting tubular secretion of creatinine. Tubular secretion is further suggested by the fact that the clearance ratio approaches unity when plasma creatinine concentration is elevated. Variations in glomerular activity are reflected in urine flow in snakes as shown by a direct relationship between clearance of inulin (GFR) and urine flow In snakes solute excretion is dependent on an increase in functional tubular population, with a concomitant increase in filtered load and not a decrease in tubular solute reabsorption. Evidence for this concept is presented and indicates that, over a tenfold increase in GFR, snakes continue to excrete about the same per cent of their filtered load. Water reabsorption, on the other hand, appears to be similar in character to that seen in higher vertebrates. Proximally, it appears to be dependent on solute reabsorption ("obligatory"), whereas distally it is influenced by ADH ("facultative").

scholarly journals Assessing glomerular filtration rate in patients with severe heart failure: comparison between creatinine-based formulas

2012 ◽  
Vol 130 (5) ◽  
pp. 289-293 ◽  
Author(s):  
Alexandre Libório ◽  
Russian Uchoa ◽  
João Neto ◽  
Juan Valdivia ◽  
Elizabeth De Francesco Daher ◽  
...  
Keyword(s):  
Heart Failure ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Serum Creatinine ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Severe Heart Failure ◽  
Creatinine Concentration ◽  
Cross Sectional ◽  
Gfr Estimation

CONTEXT AND OBJECTIVE: Severe heart failure is highly associated with chronic kidney disease (CKD). Serum creatinine is a poor indicator of renal function and glomerular filtration rate (GFR) estimation is an accessible method for assessing renal function. The most popular formulas for GFR estimation are the Cockcroft-Gault (CG), the four-variable Simplified Modification of Diet in Renal Disease (sMDRD) and the recently introduced CKD-Epidemiology Collaboration (CKD-EPI). The objective of the study was to analyze the correlation between these three equations for estimating GFR in patients with severe heart failure. DESIGN AND SETTING: Cross-sectional observational study at a university reference center. METHODS: GFR was estimated in patients with severe heart failure who were awaiting heart transplantation, using the CG, sMDRD and CKD-EPI formulas. These estimates were analyzed using Pearson's correlation and Bland-Altman analysis. RESULTS: This study included 157 patients, of whom 32 (20.3%) were female. Normal serum creatinine concentration was observed in 21.6%. The mean GFR according to CG, sMDRD and CKD-EPI was 70.1 ± 29.5, 70.7 ± 37.5 and 73.7 ± 30.1 ml/min/1.73 m²; P > 0.05. Pearson's coefficient demonstrated good correlations between all the formulas, as did Bland-Altman. However, the patients presented GFR < 60 ml/min more frequently with the sMDRD formula (54.1% versus 40.2% for CG and 43.2% for CKD-EPI; P = 0.02). CONCLUSION: Despite the good correlation and agreement between the three methods, the sMDRD formula classified more patients as presenting GFR less than 60 ml/min.

scholarly journals Augmented Renal Clearance Following Traumatic Injury in Critically Ill Patients Requiring Nutrition Therapy

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1681
Author(s):  
Roland N. Dickerson ◽  
Christin N. Crawford ◽  
Melissa K. Tsiu ◽  
Cara E. Bujanowski ◽  
Edward T. Van Matre ◽  
...  
Keyword(s):  
Serum Creatinine ◽  
Renal Clearance ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Nutrition Therapy ◽  
Serum Creatinine Concentration ◽  
Urine Collection ◽  
Augmented Renal Clearance ◽  
Creatinine Concentration ◽  
Traumatic Injuries

The intent of this study was to ascertain the prevalence of augmented renal clearance (ARC) in patients with traumatic injuries who require nutrition therapy and identify factors associated with ARC. Adult patients admitted to the trauma intensive care unit from January 2015 to September 2016 who received enteral or parenteral nutrition therapy and had a 24 h urine collection within 4 to 14 days after injury were retrospectively evaluated. Patients with a serum creatinine concentration > 1.5 mg/dL, required dialysis, or had an incomplete urine collection were excluded. ARC was defined as a measured creatinine clearance > 149 mL/min/1.73 m2. Two hundred and three patients were evaluated. One hundred and two (50%) exhibited ARC. A greater proportion of patients with ARC were male (86% vs. 67%; p = 0.004), had traumatic brain injury (33% vs. 9%; p = 0.001), a higher injury severity score (30 ± 11 vs. 26 ± 12; p = 0.015), were younger (36 ± 15 vs. 54 ± 17 years; p = 0.001), had a lower serum creatinine concentration (0.7 ± 2 vs. 0.9 ± 0.2 mg/dL; p = 0.001) and were more catabolic (nitrogen balance of −10.8 ± 13.0 vs. −6.2 ± 9.2 g/d; p = 0.004). The multivariate analysis revealed African American race and protein intake were also associated with ARC. Half of critically ill patients with traumatic injuries experience ARC. Patients with multiple risk factors for ARC should be closely evaluated for dosing of renally-eliminated electrolytes, nutrients, and medications.

scholarly journals Cystatin C: A Better Predictor of Kidney Function in Diabetic Patients

2013 ◽  
Vol 4 (1) ◽  
pp. 16-20 ◽  
Author(s):  
TS Shima ◽  
A Khatun ◽  
F Yeasmin ◽  
S Ferdousi ◽  
K Kirtania ◽  
...  
Keyword(s):  
Renal Function ◽  
Serum Creatinine ◽  
Cystatin C ◽  
Diabetic Patients ◽  
Serum Cystatin C ◽  
Creatinine Concentration ◽  
Serum Cystatin ◽  
Gault Formula ◽  
Function Impairment ◽  
Sensitivity Specificity

Serum cystatin C is a new promising marker of renal function. The aim of this study was to analyze serum cystatin C as a better predictor of renal function in diabetic nephropathy. In 60 diagnosed diabetic patients, serum cystatin C and serum creatinine were assessed. Glomerular filtration rate was estimated based on the cystatin C concentration according to Cockcroft- Gault formula and based on serum creatinine concentration according to Larsson formula. DTPA-GFR (Diethylenetriamene pentaacetate Renogram) was done as reference standard. The cross tabulation of DTPA-GFR was done with eGFR- creatinine and eGFRcystatin C. The calculated sensitivity, specificity and accuracy of eGFR- creatinine were 85%, 87.2% and 85% respectively. The eGFR- cystatin C showed higher sensitivity, specificity and accuracy than eGFR- creatinine in studied diabetic subjects. The cystatin C showed more significant correlation, r=0.78, p<0.001 than serum creatinine, r=0.59, p<0.001 with DTPA-GFR in diabetic patients. This study demonstrates that serum cystatin C may be used for early prediction for renal function impairment in diabetic kidney disease. DOI: http://dx.doi.org/10.3329/bjmb.v4i1.13777 Bangladesh J Med Biochem 2011; 4(1): 16-20

Iohexol Plasma Clearance in Animal Models: The Clear Choice for Measuring Early Renal Dysfunctio

2018 ◽  
Author(s):  
Mandy Turner
Keyword(s):  
Renal Function ◽  
Animal Models ◽  
Kidney Function ◽  
Kidney Failure ◽  
Plasma Clearance ◽  
Inulin Clearance ◽  
Plasma Creatinine ◽  
Creatinine Concentration ◽  
Plasma Creatinine Concentration ◽  
Iohexol Plasma Clearance

Glomerular filtration rate is a measure of the kidney’s ability to filter blood. In animal models of early kidney failure, there is no routine method to accurately measure GFR. The expensive gold standard of GFR measurement is exogenous inulin clearance. The commonly used method, endogenous plasma creatinine concentration, is unreliable and insensitive, especially at normal levels of renal function. This study investigates the utility of iohexol, an inexpensive radio-contrast agent as a promising exogenous marker for plasma clearance kidney function evaluation in rats. Early stages of progressive kidney failure were induced with a 0.25% adenine diet in male Sprague Dawley rats (N=8) over 5 weeks. Both plasma clearance of iohexol and inulin and creatinine concentration were evaluated following weekly venous injections and blood sampling. Plasma iohexol clearance and plasma inulin clearance strongly correlate (R2=0.95). However, plasma creatinine concentration correlated weakly with iohexol(R2=0.53) and inulin(R2=0.58). Iohexol plasma clearance accurately measures changes in kidney function, especially in in comparison to creatinine analysis. The data demonstrates creatinine is an inappropriate marker for renal function in early adenine-induced CKD rat models. Ongoing analysis of this data suggests refinement of the protocol will yield a simple method for routine measure of kidney function in murine lab animals. This tool will facilitate advancement in kidney disease onset and allow for more accurate interpretation of kidney function in the various animal models.

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