Citation Classics in Lipid Measurement and Applications (Aacc 50th Anniversary Retrospective‪)‬

In 1998 the AACC celebrates its 50th anniversary. Thus, we are honored to call attention to the outstanding professional contributions of the journal Clinical Chemistry over the years by pointing out the citation classics that have been published in its pages. By the end of 1995, 31 articles in Clinical Chemistry had been cited more than 300 times (1). Thirty of these articles were still being cited in 1995, and some are still cited to the present day. These 31 papers are distributed in multiple areas of biological sciences, and in particular: lipids, 8 papers (2-9); endocrinology, 2 papers; clinical enzymology, 4 papers; intermediary metabolism, 6 papers; renal function, 2 papers; cancer, 1 paper; and calcium metabolism, 3 papers. Publications on methodology research and laboratory applications of lipid, lipoprotein, and apolipoprotein measurements in clinical investigations and epidemiologic trials have had a major impact on research of lipid metabolism and cardiovascular medicine (2-9). The combined efforts of epidemiologists, clinicians, and laboratorians have produced classic publications on the understanding of lipid metabolic disorders, have stimulated development of new novel equipment and methodology, and have helped to establish the development of beneficial preventive and control measures for diseases of the heart and blood vessels. The cited lipid papers published in Clinical Chemistry included mainly the original papers on measurement of lipoproteins, enzymatic measurements of cholesterol and triglycerides, and immunoassays of apolipoproteins. The method used most widely today for estimation of the concentration of LDL-cholesterol (LDL-C) in both clinical and research laboratories arose from the publication of Friedewald et al. (2) that showed that the serum concentration of LDL-C can be estimated from available established measurements of total cholesterol (TC), HDL-cholesterol (HDL-C), and triglyceride (TG) in serum (Fig. 1.). Prior to this, only time-consuming and expensive ultra-centrifugal measurements were used to determine LDL-C in serum. The ability to calculate LDL-C thus permitted greater worldwide access to LDL-C estimates and allowed for the greater application of the more sensitive and specific LDL-C estimates in lieu of, or in conjunction with, TC in the assessment of coronary heart disease risk. The Friedewald equation has since been used as the basis of LDL-C estimation in several landmark trials of the clinical benefits of lipid modification, thus demonstrating its important role in the epidemiology of coronary heart disease.