Calculated LDL-C: Time to Move On?

Abstract

Despite its shortcomings, the Friedewald equation is still being used today in most clinical laboratories to calculate low-density lipoprotein-cholesterol (LDL-C). Updated equations have been proposed to circumvent some of the problems of LDL-C calculation. A recent article by White-Al Habeeb et al. 1 White-Al Habeeb N.M.A. Higgins V. Venner A.A. et al. Canadian Society of Clinical Chemists Working Group on Reference Interval HarmonizationCanadian Society of Clinical Chemists harmonized clinical laboratory lipid reporting recommendations on the basis of the 2021 Canadian Cardiovascular Society Lipid Guidelines. Can J Cardiol. 2022; 38: 1180-1188 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar in this journal recommended implementation of the new National Institutes of Health (NIH) equation 2 Samson M. Ling C. Sun Q. et al. A new equation for calculation of low-density lipoprotein cholesterol in patients with normolipidemia and/or hypertriglyceridemia. JAMA Cardiol. 2020; 5: 540-548 Crossref PubMed Scopus (117) Google Scholar rather than the Friedewald calculation. The authors stated that the new NIH equation “allows for calculation of LDL-C up to triglyceride 9.04 mmol/L.” Canadian Society of Clinical Chemists Harmonized Clinical Laboratory Lipid Reporting Recommendations on the Basis of the 2021 Canadian Cardiovascular Society Lipid GuidelinesCanadian Journal of CardiologyVol. 38Issue 8PreviewThere is limited guidance on laboratory reporting and interpretation of lipids and lipoproteins used in cardiovascular risk stratification. This contributes to inconsistencies in lipid reporting across clinical laboratories. Recently, the Canadian Cardiovascular Society (CCS) published the 2021 CCS guidelines for the management of dyslipidemia for the prevention of cardiovascular disease in the adult. A subcommittee of the Working Group on Reference Interval Harmonization of the Canadian Society of Clinical Chemists has developed harmonized lipid reporting recommendations that are aligned with the 2021 CCS guidelines, to improve the standardization of lipid assessment and clinical decision-making. Full-Text PDF Reply to Cartier et al.—Response to Calculated LDL-C: Time to Move On?Canadian Journal of CardiologyPreviewWe recommended laboratories implement the National Institutes of Health (NIH) equation, to replace the Friedewald equation, for calculating low-density lipoprotein cholesterol (LDL-C) in all patients.1 In response, Cartier et al. argue that as LDL-C is an inferior marker to non–high-density lipoprotein cholesterol (HDL-C) and apolipoprotein B (apoB) for atherogenicity when triglycerides (TG) > 1.50 mmol/L, LDL-C calculation should be omitted when not pertinent. We agree that non–HDL-C and apoB are superior when TG is elevated; however, it is still important to clinically report accurate LDL-C values, when possible. Full-Text PDF