Cholesterol

Performed in Chemistry

CHOL

Green Top LiHep, Plasma
WyMCC - SST

Gold/SST or Red Top

Wrong tube type, hemolysis, icteric, lipemic or contaminated sample.

Daily, Sunday through Saturday

Less than 4 hours

Cholesterol is a steroid with a secondary hydroxyl group in C3 position. It is synthesized in many types of tissue, but particularly in liver and intestinal wall. Approximately three quarters of cholesterol is newly synthesized and a quarter originates from dietary intake. Cholesterol assays are used for screening for atherosclerotic risk and in diagnosis and treatment of disorders involving elevated cholesterol levels as well as lipid and lipoprotein metabolic disorders. Cholesterol analysis was first reported by Liebermann in 1885 followed by Burchard in 1889. In Liebermann-Burchard reaction, cholesterol forms a bluegreen dye from polymeric unsaturated carbohydrates in an acetic acid/acetic anhydride/concentrated sulfuric acid medium. Abell and Kendall method is specific for cholesterol, but is technically complex and requires the use of corrosive reagents. In 1974, Roeschlau and Allain described the first fully enzymatic method. This method is based on determination of Δ4-cholestenone after enzymatic cleavage of the cholesterol ester by cholesterol esterase, conversion of cholesterol by cholesterol oxidase, and subsequent measurement by the Trinder reaction of hydrogen peroxide formed. Optimization of ester cleavage (> 99.5 %) allows standardization using primary and secondary standards and a direct comparison with CDC and NIST reference methods. Nonfasting sample results may be slightly lower than fasting results. Roche cholesterol assay meets 1992 National Institutes of Health (NIH) goal of less than or equal to 3 % for both precision and bias. Assay is optionally standardized against Abell/Kendall and isotope dilution/mass spectrometry. Performance claims and data presented here are independent of thestandardization.