ABC | Volume 111, Nº5, November 2018

Counterpoint Izar Flexibilization of fasting: science or convenience Arq Bras Cardiol. 2018; 111(5):750-752 however, when corrected for albumin, reflecting fluid intake, the difference disappeared, and was attributed to the fluid and not to the diet. 20 Second, we live most of our time in non-fasting state. Non‑fasting and fasting lipid concentrations vary similarly over time and are at least equivalent in the prediction of cardiovascular disease. In fact, data from the Calgary Laboratory Services in Canada demonstrated that in ~200,000 men and women, total cholesterol, HDL and LDL-cholesterol did not vary as a function of the period of fasting after the last meal. 17 Third, reference plasma lipid, lipoprotein, and apolipoprotein concentration values based on desirable concentration cutoff points, do not vary when non-fasting, except for triglycerides, which should be flagged as abnormal in laboratory reports > 175 mg/dL. However, non-fasting triglycerides were better predictors than in the fasting state. 7 Fourth, the risk of ischemic heart disease and myocardial infarction in 92,285 individuals from the Copenhagen General Population Study recruited from 2003 through 2014, could be predicted by non-fasting lipids (reported in Nordestgaard et al. 7 ). Fifth, a novel method to estimate LDL-C using an adjustable factor for the TG:VLDL-C ratio provided a more accurate guideline risk classification than the Friedewald equation. 21 The authors used a large convenience sample of consecutive clinical lipid profiles obtained from 2009 through 2011 (n = 1,350,908), including children, adolescents, and adults in the United States). The sample was randomly assigned to derivation (n = 900,605) or validation (n = 450,303) data sets. Results closely matched those in the National Health and Nutrition Examination Survey (NHANES). This estimation method provided higher-fidelity estimates than the Friedewald equation. The greatest improvement in concordance occurred when classifying LDL-C lower than 70 mg/dL, especially in patients with high triglyceride levels. Indeed, there is a need for external validation, and assessment of its clinical importance. However, this novel method could be implemented in most laboratory reporting systems with virtually no cost. Finally, what would be the problem to add convenience to science? Postprandial measurements are more practical and provide the patient a greater access to the laboratory, and also can decrease the number of missed working days and medical appointments due to missed tests; blood collection in the postprandial state is safer in several circumstances and help prevent hypoglycemia secondary to the use of insulin in patients with diabetes mellitus, in pregnant women, children, and elderly individuals, reducing complications and increasing adherence to the tests and to medical appointments; flexibilization of fasting for lipid profiling, can bring more comfort to the patient and greater amplitude of schedules in the laboratories, especially in the morning; technological advances in diagnostic methods, can mitigate the interference of sample turbidity when triglycerides are high. 22 If, fasting is not routinely required for assessing the plasma lipid profile, some recommendations should bemade in specific situations: 1) when non-fasting plasma triglyceride concentration exceed 440 mg/dL, consideration should be given to repeating the lipid profile in the fasting state; 2) laboratory reports should flag abnormal values based on desirable concentration cut-off points; 3) life-threatening or extremely high concentrations should trigger an immediate referral to a lipid clinic or to a physician with special interest in lipids. 7,22 Author contributions Conception and design of the research, Acquisition of data, Analysis and interpretation of the data, Statistical analysis, Writing of the manuscript and Critical revision of the manuscript for intellectual content: Izar MCO. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. 1. Bailie EE. Report from the Laboratory Standardization PaneI of the National CholesterolEducationProgram:recommendations for improvingcholesterol measurement. 1993. LabMedicine. 1990;21(7):429-35. (NIH Publication N° 93-2964). 2. Catapano AL, Reiner Z, De Backer G, Graham I, Taskinen MR, Wiklund O, et al; European Society of Cardiology (ESC); European Atherosclerosis Society (EAS). ESC/EAS Guidelines for the management of dyslipidaemias The Task Force for the management of dyslipidaemias of the European Society of Cardiology (ESC) and the European Atherosclerosis Society (EAS). Atherosclerosis. 2011;217(1):3-46. 3. Xavier HT, Izar MC, Faria Neto JR, Assad MH, Rocha VZ, Sposito AC, et al. [V Brazilian guidelines on dyslipidemias and prevention of atherosclerosis]. Arq Bras Cardiol. 2013;101(4 Suppl 1):1-20. 4. FriedewaldWT, Lavy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499-502. 5. Sociedade Brasileira de Patologia Clínica/Medicina Laboratorial. SBPC. Brazilian Society of Clinical Pathology. Laboratory determination of the lipid profile. [Cited in 2016 Dec 10]. Available from: http://www.sbpc.org . br/upload/conteudo/consenso_jejum_dez2016_final.pdf 6. Faludi AA, Izar MC, Saraiva JF, Chacra AP, Bianco HT, Afiune Neto A, et al. Atualização da Diretriz Brasileira de dislipidemias e prevenção da aterosclerose – 2017. Arq Bras Cardiol. 2017;109(2 Supl.1):1-76. 7. Nordestgaard BG, Langsted A, Mora S, Kolovou G, Baum H, Bruckert E, et al; European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) joint consensus References 751