Documento de consenso: recomendaciones sobre la utilización de ecuaciones para la estimación del filtrado glomerular en niños / Consensus document: Recommendations for the use of equations to estimate glomerular filtration rate in children

La aparición de las guías K/DOQI en el año 2002 sobre definición, evaluación y clasificación en estadios de la enfermedad renal crónica (ERC) han supuesto un cambio importante en la forma de evaluar la función renal en adultos y en niños. Estas guías, recientemente actualizadas, recomiendan que el estudio de la función renal se realice a partir de la medida de la concentración sérica de creatinina y de la estimación del filtrado glomerular (FG) obtenido mediante una ecuación. Sin embargo, la implementación de esta recomendación en los informes del laboratorio clínico en población pediátrica ha sido casi nula. Los estudios aparecidos en los últimos años sobre la importancia de la detección y seguimiento de los pacientes con ERC, la aparición de nuevas ecuaciones de estimación del FG y los avances en los laboratorios clínicos respecto a los métodos de medida de creatinina y de cistatina C han determinado la colaboración entre los servicios de pediatría y de los laboratorios clínicos con objeto de establecer recomendaciones homogéneas y basadas en la mejor evidencia científica sobre la utilización de las ecuaciones de estimación del FG en este grupo de población. El objetivo de este documento es proporcionar recomendaciones sobre la evaluación de la función renal y la utilización de ecuaciones de estimación del FG en niños. Los destinatarios de estas recomendaciones son los pediatras, nefrólogos, bioquímicos clínicos, analistas clínicos y todos los profesionales de la salud relacionados con el estudio y la evaluación de la función renal de este grupo de pacientes (AU)

The appearance of the K/DOQI guidelines in 2002 on the definition, evaluation and staging of chronic kidney disease (CKD) have led to a major change in how to assess renal function in adults and children. These guidelines, recently updated, recommended that the study of renal function is based, not only on measuring the serum creatinine concentration, but this must be accompanied by the estimation of glomerular filtration rate (GFR) obtained by an equation. However, the implementation of this recommendation in the clinical laboratory reports in the paediatric population has been negligible. Numerous studies have appeared in recent years on the importance of screening and monitoring of patients with CKD, the emergence of new equations for estimating GFR, and advances in clinical laboratories regarding the methods for measuring plasma creatinine and cystatin C, determined by the collaboration between the departments of paediatrics and clinical laboratories to establish recommendations based on the best scientific evidence on the use of equations to estimate GFR in this population. The purpose of this document is to provide recommendations on the evaluation of renal function and the use of equations to estimate GFR in children from birth to 18 years of age. The recipients of these recommendations are paediatricians, nephrologists, clinical biochemistry, clinical analysts, and all health professionals involved in the study and evaluation of renal function in this group of patients (AU)

[Consensus document: recommendations for the use of equations to estimate glomerular filtration rate in children]. / Documento de consenso: recomendaciones sobre la utilización de ecuaciones para la estimación del filtrado glomerular en niños.

The appearance of the K/DOQI guidelines in 2002 on the definition, evaluation and staging of chronic kidney disease (CKD) have led to a major change in how to assess renal function in adults and children. These guidelines, recently updated, recommended that the study of renal function is based, not only on measuring the serum creatinine concentration, but this must be accompanied by the estimation of glomerular filtration rate (GFR) obtained by an equation. However, the implementation of this recommendation in the clinical laboratory reports in the paediatric population has been negligible. Numerous studies have appeared in recent years on the importance of screening and monitoring of patients with CKD, the emergence of new equations for estimating GFR, and advances in clinical laboratories regarding the methods for measuring plasma creatinine and cystatin C, determined by the collaboration between the departments of paediatrics and clinical laboratories to establish recommendations based on the best scientific evidence on the use of equations to estimate GFR in this population. The purpose of this document is to provide recommendations on the evaluation of renal function and the use of equations to estimate GFR in children from birth to 18 years of age. The recipients of these recommendations are paediatricians, nephrologists, clinical biochemistry, clinical analysts, and all health professionals involved in the study and evaluation of renal function in this group of patients.

Consensus document. Recommendations on assessing proteinuria during the diagnosis and follow-up of chronic kidney disease.

The presence of persistently elevated urinary concentrations of protein or albumin is considered a sign of kidney damage. The diagnosis and staging of chronic kidney disease (CKD) is nowadays based upon the presence of signs of kidney damage together with the estimation of the glomerular filtration rate.The presence of either proteinuria or albuminuria identifies a group of patients with higher risk of CKD progression and higher cardiovascular risk. Treatment with angiotensin converting enzyme inhibitors or angiotensin-receptor blockers,for instance, decreases both the progression of CKD and the incidence of cardiovascular events and death in patients with CKD and proteinuria. Thus, proteinuria is currently considered a therapeutic target by itself. Despite of the importance of detecting and monitoring proteinuria in the diagnosis and follow-up of CKD, there is not a consensus among the clinical practice guidelines published by different scientific societies on the diagnostic cut-off levels, on different sampling procedures,on the units used in laboratory reports or just on whether it should be defined in terms of albumin or proteinuria. The goal of this document, created by the consensus of the Spanish Society of Clinical Biochemistry and Molecular Pathology(SEQC, representing its spanish acronym) and the Spanish Society of Nephrology (S.E.N.), is to recommend to medical and laboratory clinicians appropriate guidelines for the detection and monitorization of proteinuria as a marker of CKD in adults and children. These recommendations result from searching,evaluating and summarizing current scientific evidence published in the last years.

Por qué y cómo hemos de analizar los cálculos urinarios / Why and how we must analyse urinary calculi

Contexto: Existe una heterogeneidad de criterio sobre la utilidad del análisis del cálculo urinario, así como de cuál es la metodología más adecuada. En esta revisión se presenta el análisis de la litiasis mediante la técnica del estudio morfoconstitucional basada en la combinación de la microscopía estereoscópica (MEST) con el estudio de infrarrojos (EIR). Resumen de evidencia: Existen múltiples técnicas de análisis del cálculo: análisis químico, microscopía electrónica, difracción por rayos X, MEST y EIR. Mediante la revisión de cada una de estas técnicas y el estudio de varios casos clínicos, el presente trabajo muestra la utilidad clínica del análisis del cálculo, así como las ventajas e inconvenientes de cada uno de los citados métodos. Por otro lado, se evidencia cómo el análisis mediante el estudio morfoconstitucionales el que más información clínica de utilidad ofrece al urólogo. Asimismo, se presenta la clasificación de las litiasis basadas en este método y su correlación clínica con el paciente. Conclusiones: El análisis del cálculo mediante la técnica del estudio morfoconstitucional aporta más información que el resto de técnicas y permite establecer una clasificación del cálculo de gran utilidad clínica y diagnóstica (AU)

Context: There is heterogeneity of criteria on the utility of urinary stone analysis as well as on which is the most suitable methodology. This review presents the analysis of the lithiasis using the morphoconstitutional analysis technique based on the combination of the stereoscopic microscopy (SM) with infrared study (IRS). Summary of the evidence: There are many techniques to analyze the stone: chemical analysis, electron microscopy, X-ray diffraction, SM and IRS. Reviewing each one of these techniques and through the study of several clinical cases, this review shows the usefulness of stone analysis and the pros and cons of each one of the mentioned techniques. Furthermore, it can be clearly seen how the morphoconstitutional analysis is the one that offers the most useful clinical information to the urologist. In addition, classification of the lithiasis based on this method and its clinical correlation with patients is presented. Conclusions: Using the morphoconstitutional study to analyze the stone offers more information than the other techniques and it makes it possible to establish a stone classification of important clinical and diagnostic utility (AU)

Documento de Consenso. Recomendaciones sobre la valoración de la proteinuria en el diagnóstico y seguimiento de la enfermedad renal crónica / Consensus Document. Recommendations on assessing proteinuria during the diagnosis and follow-up of chronic kidney disease

La presencia de concentraciones elevadas de proteína o albúmina en orina, de modo persistente, es un signo de lesión renal y constituye, junto con la estimación del filtrado glomerular, la base sobre la que se sustenta el diagnóstico de la enfermedad renal crónica (ERC). Su presencia identifica a un grupo de pacientes con un riesgo superior de progresión de la enfermedad renal y con mayor morbilidad cardiovascular. El tratamiento con inhibidores de la enzima de conversión de la angiotensina o antagonistas del receptor de la angiotensina, en individuos con ERC y proteinuria, ha demostrado que disminuye tanto la progresión de la enfermedad renal como la incidencia de eventos cardiovasculares y muerte, por lo que la disminución del valor de la proteinuria es considerado un objetivo terapéutico. Pese a la importancia de la detección y monitorización de la proteinuria en el diagnóstico y seguimiento de la ERC, no existe consenso entre las guías de práctica clínica publicadas por distintas Sociedades científicas sobre cuáles son los valores que indican su presencia, si ésta debe ser definida en términos de albúmina o de proteína, el espécimen más adecuado para su medida o el tipo de unidades en que deben ser expresados los resultados. La finalidad de este documento, elaborado con el consenso de la Sociedad Española de Bioquímica Clínica y Patología Molecular (SEQC) y la Sociedad Española de Nefrología (S.E.N.), es proporcionar recomendaciones, a los facultativos clínicos y de laboratorio, para la detección y monitorización de la proteinuria como marcador de la presencia de ERC en adultos y en niños. Las recomendaciones son el resultado de la búsqueda, evaluación y síntesis de la evidencia científica publicada sobre el tema en los últimos años (AU)

The presence of persistently high urinary concentrations of protein or albumin is considered a sign of kidney damage. Nowadays, the diagnosis of chronic kidney disease (CKD) is based on the presence of signs of kidney damage together with the estimation of the glomerular filtration rate. The presence of either proteinuria or albuminuria identifies a group of patients with a higher risk of progression of CKD and higher cardiovascular risk. Treatment with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers decreases both the progression of CKD and the incidence of cardiovascular events and death in patients with CKD and proteinuria. Thus, proteinuria is currently considered a therapeutic target by itself. Despite the importance of detecting and monitoring proteinuria in the diagnosis and follow-up of CKD, there is no consensus among the clinical practice guidelines published by different scientific societies on the diagnostic cut-off levels, on different sampling procedures, on the units used in laboratory reports or just on whether it should be defined in terms of albuminuria or proteinuria. The goal of this document, created with the agreement of the Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC, representing its Spanish acronym) and the Spanish Society of Nephrology (S.E.N.), is to recommend appropriate guidelines to medical and laboratory physicians for detecting and monitoring proteinuria as a marker of CKD in adults and children. These recommendations are the result of searching, evaluating and summarising current scientific evidence published in the last few years (AU)

[Why and how we must analyse urinary calculi]. / Por qué y cómo hemos de analizar los cálculos urinarios.

CONTEXT: There is heterogeneity of criteria on the utility of urinary stone analysis as well as on which is the most suitable methodology. This review presents the analysis of the lithiasis using the morphoconstitutional analysis technique based on the combination of the stereoscopic microscopy (SM) with infrared study (IRS). SUMMARY OF THE EVIDENCE: There are many techniques to analyze the stone: chemical analysis, electron microscopy, X-ray diffraction, SM and IRS. Reviewing each one of these techniques and through the study of several clinical cases, this review shows the usefulness of stone analysis and the pros and cons of each one of the mentioned techniques. Furthermore, it can be clearly seen how the morphoconstitutional analysis is the one that offers the most useful clinical information to the urologist. In addition, classification of the lithiasis based on this method and its clinical correlation with patients is presented. CONCLUSIONS: Using the morphoconstitutional study to analyze the stone offers more information than the other techniques and it makes it possible to establish a stone classification of important clinical and diagnostic utility.

Valoración de la nueva ecuación CKD-EPI para la estimación del filtrado glomerular / Assessment of the new CKD-EPI equation to estimating glomerular filtration rate

Introducción: Recientemente el grupo CKD-EPI (ChronicKidney Disease Epidemiology Collaboration) ha publicado una nueva ecuación de estimación del filtrado glomerular(FG) desarrollada a partir de una población de 8.254 individuosa los que se midió el FG mediante aclaramiento de iotalamato (media 68 ml/min/1,73 m2, DE 40ml/min/1,73 m2), y que incluye como variables la creatinina sérica, la edad, el sexo y la raza, con distintas versiones en función de la etnia, el sexo y el valor de la creatinina. La ecuación de CKD-EPI mejoró los resultados en cuanto a exactitud y precisión de la ecuación de elección actual MDRD-IDMS (Modification of Diet in Renal Disease-Isotopic Dilution Mass Spectrometry) en especial para valores de FG superior a 60 ml/min/1,73 m2 en un grupo de 3.896individuos. Material y métodos: El objetivo de nuestro estudio fue comparar los valores de FG estimado utilizando la nueva ecuación de CKD-EPI frente a MDRD-IDMS en una amplia cohorte de 14.427 pacientes (5.234 mujeres y 9.193hombres) y analizar las repercusiones que el uso de CKDEPI tendría a la hora de clasificar a la población en distintos estadios de enfermedad renal crónica (ERC) en función de su FG. Resultados: La media del FG estimado fue 0,6ml/min/1,73 m2 más alto por CKD-EPI que por MDRD-IDMS en el grupo total, 1,9 ml/min/1,73 m2 más alto en el grupo (..) (AU)

Introduction: A recent report by the CKD-EPI Chronic Kidney Disease Epidemiology Collaboration) group describes a new equation to estimate the glomerular filtration rate (GFR).This equation has been developed from a population of8,254 subjects who had the GFR measured by iothalamate clearance (mean 68 ml/min/1.73 m2, SD 40 ml/min/1.73 m2).It includes variables such as serum creatinine, age, sex and race with different formula according to race, sex and creatinine value. The CKD-EPI equation improved the accuracy and precision results of the current first-choice MDRDIDMS(Modification of Diet in Renal Disease-Isotopic Dilution Mass Spectrometry) formula, specially for GFR >60ml/min/1.73 m2 in a group of 3,896 subjects. Methods: The goal of our study was to compare the estimated GFR by using the new equation CKD-EPI with MDRD-IDMS in a wide cohort of 14,427 patients (5,234 women and 9,193 men),and to analyze the impact of the new CKD-EPI formula on (AU)

[Assessment of the new CKD-EPI equation to estimate the glomerular filtration rate]. / Valoración de la nueva ecuación CKD-EPI para la estimación del filtrado glomerular.

INTRODUCTION: A recent report by the CKD-EPI Chronic Kidney Disease Epidemiology Collaboration) group describes a new equation to estimate the glomerular filtration rate (GFR). This equation has been developed from a population of 8,254 subjects who had the GFR measured by iothalamate clearance (mean 68 mL/min/1.73 m2, SD 40 mL/min/1.73 m2). It includes variables such as serum creatinine, age, sex and race with different formula according to race, sex and creatinine value. The CKD-EPI equation improved the accuracy and precision results of the current first-choice MDRD-IDMS (Modification of Diet in Renal Disease-Isotopic Dilution Mass Spectrometry) formula, specially for GFR > 60 mL/min/1.73 m2 in a group of 3,896 subjects. METHODS: The goal of our study was to compare the estimated GFR by using the new equation CKD-EPI with MDRD-IDMS in a wide cohort of 14,427 patients (5,234 women and 9,193 men), and to analyze the impact of the new CKD-EPI formula on the staging of patients with CKD. RESULTS: Mean estimated GFR was 0.6 mL/min/1.73 m2 higher with CKD-EPI as compared to MDRD-IDMS for the whole group, 1.9 mL/min/1.73 m2 higher for women and 0.2 mL/min/1.73 m2 lower for men. The percentage of CKD staging concordancy between equations varied from 79.4 % for stage 3A and 98.6% for stage 5. For those patients younger than 70 years, 18.9 % and 24 % MDRD-IDMS stages 3B and 3A were reclassified as CKD 3A and 2 by CKD-EPI, respectively. For the same stages in the group younger than 70 years, the percentage of reclassified patients increased up to 34.4% and 33.4%, respectively. CONCLUSION: The new CKD-EPI equation to estimate the GFR reclassifies an important number of patients to higher CKD stages (higher GFR), specially younger women, classified as CKD stage 3 by MDRD-IDMS.

[Evaluation of a new strategy for detecting thyroid dysfunction]. / Evaluación de una nueva estrategia para la detección de disfunción tiroidea.

The results of a diagnostic strategy to evaluate thyroid function were assessed. This strategy consists of TSH measurement as the initial biochemical test, assuming that all individuals with normal TSH concentrations are euthyroid and do not require additional measurements of other hormones. The study was carried out in 576 patients whose serum samples had been referred to the laboratory during 4 consecutive weeks for the evaluation of thyroid function. In all cases TSH and free T4 (FT4) concentrations were measured by chemoluminescence, using one tube for each parameter and patient. Total T3 concentrations (T3) were only measured (RIA) in patients with subnormal TSH values, using duplicate samples. With TSH measurement as the initial test, 447 patients (78%) in whom further hormone assessment would not have been required were detected. This rate would have been 75% if FT4 measurement had been adopted as the screening test. In addition, 55 patients with subclinical thyroid dysfunction were identified with TSH measurement. They would have been missed if the screening had been based on FT4 only. T3 measurement only contributed to the identification of one patient with T3 thyrotoxicosis, and it did not provide additional useful information for the diagnostic classification of the remaining patients. The results of these assays show that TSH measurement is the biochemical test of choice as the first step of a strategy to detect thyroid dysfunction. Its use to this end makes the concomitant measurement of other hormonal parameters unnecessary, resulting in a considerable reduction of cost.