What is the goal of the saponification step in the Abell-Kendall method for cholesterol measurement?

The goal of the saponification step in the Abell-Kendall method for cholesterol measurement is to convert cholesterol esters to free cholesterol. This is a crucial step because cholesterol is often found in the body in the form of esters, which are esters of fatty acids. Saponification involves the use of an alkaline solution that hydrolyzes these esters, releasing free cholesterol that can then be further processed and quantified in the subsequent steps of the assay. By converting the cholesterol esters to their free form, the assay accurately measures the total cholesterol content, including that which is esterified. This provides a more comprehensive representation of cholesterol levels in the sample, which is essential for diagnostic purposes.