Aims: To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. Methods and Results: Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1-6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; -0.2 mmol/L (8 mg/dL) for total cholesterol; -0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; -0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/nonfasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, whereas fasting sampling may be considered when non-fasting triglycerides are >5 mmol/L (440 mg/dL). For nonfasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral for the risk of pancreatitis when triglycerides are >10 mmol/L (880 mg/dL), for homozygous familial hypercholesterolemia when LDL cholesterol is >13 mmol/L (500 mg/dL), for heterozygous familial hypercholesterolemia when LDL cholesterol is >5 mmol/L (190 mg/dL), and for very high cardiovascular risk when lipoprotein(a) >150 mg/dL (99th percentile). Conclusions: We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cutpoints. Non-fasting and fasting measurements should be complementary but not mutually exclusive.

Objetivos: Evaluar criticamente las implicaciones clinicas de la utilizacion del perfil lipidico sin ayuno en lugar de perfiles de lipidos con ayuno y proporcionar orientacion para la elaboracion de informes de laboratorio sobre perfiles lipidicos anormales con ayuno y sin ayuno. Metodos y Resultados: Abundantes datos observacionales, en los que perfiles lipidicos medidos aleatoriamente sin ayuno se han comparado con perfiles lipidicos determinados en condiciones de ayuno, indican que las variaciones medias maximas de 1-6 h despues de ingestas habituales no son clinicamente significativas [+0,3 mmol/L (+26 mg/dL) para trigliceridos; -0,2 mmol/L (-8 mg/dL) para colesterol total; -0,2 mmol/L (-8 mg/dL) para colesterol-LDL; +0,2 mmol/L (+8 mg/dL) para colesterol de remanentes calculado; -0,2 mmol/L (-8 mg/dL) para el colesterol no-HDL calculado]; las concentraciones de colesterol-HDL, apolipoproteina A1, apolipoproteina B, y lipoproteina(a) no se ven afectados por el estado de ayuno/ no ayuno. Ademas, las concentraciones en ayunas y sin ayuno varian de manera similar con el tiempo y son comparables en la prediccion de la enfermedad cardiovascular. Para mejorar el cumplimiento del paciente con las condiciones para la determinacion del perfil lipidico, por lo tanto, se recomienda el uso rutinario de los perfiles lipidicos sin ayuno, mientras que se puede considerar la toma de muestra en ayunas cuando los trigliceridos sin ayuno son >5 mmol/L (440 mg/dL). Para las muestras sin ayuno, los informes de laboratorio deberian marcar como concentraciones anormales a trigliceridos ≥2 mmol/L (175 mg/dL), colesterol total ≥5 mmol/L (190 mg/dL), colesterol-LDL ≥3 mmol/L (115 mg/dL), colesterol remanente calculado ≥0,9 mmol/L (35 mg/dL), colesterol no-HDL calculado ≥3.9 mmol/L (150 mg/dL), HDL colesterol ≤1 mmol/L (40 mg/dL), apolipoproteina A1 ≤1,25 g/L (125 mg/dL), apolipoproteina B ≥1,0 g/L (100 mg/dL), y lipoproteina(a) ≥50 mg/dL (percentil 80); para muestras con ayuno, las concentraciones anormales corresponden a trigliceridos ≥1,7 mmol/L (150 mg/dL). Aquellas concentraciones que ponen en peligro la vida requieren derivacion inmediata debido al riesgo de pancreatitis cuando los trigliceridos son >10 mmol/L (880 mg/dL), de hipercolesterolemia familiar homocigotica cuando el colesterol-LDL es >13 mmol/L (500 mg/dL) o hipercolesterolemia familiar heterocigota cuando el colesterol-LDL es >5 mmol/L (190 mg/dL), y debido al riesgo cardiovascular muy alto cuando la lipoproteina(a) es >150 mg/dL (percentil 99). Conclusiones: Recomendamos la utilizacion de rutina de muestras de sangre sin ayuno para la evaluacion del perfil lipidico plasmatico. Los informes de laboratorio deberian marcar resultados anormales basandose en valores de corte deseables. Las determinaciones con ayuno y sin ayuno deben ser complementarias, pero no se excluyen mutuamente.

HISTÓRICO: A redução da função renal basal é um fator de risco bem definido para a progressão da doença renal crônica (DRC). Avaliamos a taxa de filtração glomerular (TFG) medida e os marcadores séricos creatinina, cistatina C e proteína χ-traço (PBT) para a acurácia diagnóstica na definição do estágio da lesão renal e como preditores do risco de progressão da DRC. MÉTODOS: Dosamos as concentrações dos marcadores em 227 pacientes com DRC primária não diabética e com vários graus de lesão renal e seguimos 177 pacientes prospectivamente por até sete anos para avaliar a progressão da DRC. RESULTADOS: No início, creatinina, cistatina C e PBT se correlacionaram fortemente com a TFG medida pela depuração do ioexol. As concentrações dos três marcadores aumentaram progressivamente com a diminuição da TFG, e seus desempenhos diagnósticos para a detecção até mesmo de discretas deteriorações da função renal (TFG < 90 ml/min/1,73 m2) foram similares. Sessenta e cinco pacientes tiveram progressão da DRC, definida como duplicação da creatinina inicial e/ou falência renal terminal durante o seguimento prospectivo. Esses pacientes eram mais velhos e tinham, inicialmente, menor TFG e valores mais altos de creatinina, cistatina C e PBT (todos p < 0,001) comparados com os pacientes que não alcançaram o endpoint renal pré-definido. As análises de regressão de risco proporcional de Cox revelaram que os três marcadores de depuração eram igualmente fortes preditores da progressão da DRC, mesmo após os ajustes para idade, sexo, TFG e proteinúria. CONCLUSÃO: O desempenho diagnóstico da creatinina sérica, da cistatina C ou da PBT na detecção até mesmo de discretos graus de deterioração da função renal é boa, e esses marcadores fornecem previsão do risco de progressão da doença renal em pacientes com DRC.

INTRODUCTION: Impaired baseline kidney function is a well-defined risk factor for progression of chronic kidney disease (CKD). We evaluated measured glomerular filtration rate (GFR) and the serum markers creatinine, cystatin C, and χ-trace protein (BTP) for diagnostic accuracy in defining the stage of kidney impairment and as risk predictors of CKD progression. METHODS: We measured serum marker concentrations in 227 patients with primary nondiabetic CKD and various degrees of renal impairment and followed 177 patients prospectively for up to seven years to assess progression of CKD. RESULTS: At baseline, creatinine, cystatin C, and BTP were strongly correlated with GFR as measured by iohexol clearance. Concentrations of all three markers increased progressively with decreasing GFR, and their diagnostic performance for the detection of even minor deteriorations of renal function (GFR < 90 ml · min-1 · (1.73 m²)-1) was similar. Sixty-five patients experienced progression of CKD, defined as doubling of baseline creatinine and/or terminal renal failure during prospective follow-up. These patients were older and had a lower GFR and higher serum creatinine, cystatin C, and BTP values at baseline (all p < 0.001) compared with the patients who did not reach a predefined renal endpoint. Cox proportional hazard regression analysis revealed that all three clearance markers were equally strong predictors of CKD progression, even after adjustment for age, sex, GFR, and proteinuria. CONCLUSION: The diagnostic performance of serum creatinine, cystatin C, or BTP for detecting even minor degrees of deterioration of renal function is good, and these markers provide reliable risk prediction for progression of kidney disease in patients with CKD.