Lipid nomenclature; recommendations regarding the reporting of serum lipids and lipoproteins made by the Committee on Lipid and Lipoprotein Nomenclature of the American Society for the Study of Arteriosclerosis.

1. The factor 1.67 to be used to convert the weight of cholesterol present in the esterified form into weight of cholesterol ester. (Kelsey and Longenecker, J. Biol. Chem. 139:727,1941) 2. The ratio free cholesterol/total cholesterol to be expressed as a decimal and to be the accepted form of expressing the relative quantities of free and esterified cholesterol. 3. The factor 25 to be used to convert lipid phosphorus to phospholipid. It has the authority of tradition. 4. The amount of phosphorus in a Bloor extract to be considered the correct lipid phosphorus content of serum. Van Slyke has shown that inorganic phosphorus does not contaminate the extract. (J. Biol. Chem. 200: 525, 1953) 5. The relative amounts of cholesterol and phospholipid to be expressed as the ratio total cholesterol/phospholipid, as a decimal. Values used should represent weights not moles. 6. Triglycerides and fatty acids to be reported as triglycerides, which predominate. In most analytic procedure they are not separated. The term "neutral fat," which is ambiguous, to be avoided or to be specifically defined. Triglycerides to be reported in mg. The use of milliequivalents to be confined to values for fatty acids determined by titration when additional determinations are not available for the calculation of triglycerides. 7. In our present state of knowledge no uniform classification of lipoproteins is possible. Their composition, and hence their physical properties, vary in disease and perhaps in health. It is therefore not possible to correlate alcohol solubility, electrophoretic mobility and density. 8. The term Sf to be confined to flotation rates at a density of 1.063. Flotation rates at other densities to be expressed as _S with the density as subscript. 9. The terms alpha and beta lipoprotein to be confined to electrophoretic analyses. 10. Lipoproteins separated by Cohn fractionation to be designated by the appropriate fraction. 11. All methods employed to be described or appropriate references cited.