[Historical Aspects of Cholesterol Value by Various Analytical Methods]

Chemical analysis, which had been used for routine test until enzymatic analysis was developed by Richmond in 1973, gave 10% or much higher systematic error on serum cholesterol level compared to orthodox reference method. Direct analysis without deproteinization, which was used widely in the 1960's because of ease of use, gave even more erroneous value caused by interference depending on each sample. Although cholesterol oxidase method is good, its reliability depends on reagent kit or instrument. Therefore, in reality, the method shows unexpected large interlaboratory differences. At this stage it is impossible to discuss the meaning of 10-20 mg/dl difference on serum cholesterol level.