Abstract: Provided are a method which enables more accurate quantification of lipoprotein cholesterol in a test sample, and a quantification reagent and a quantification kit used for this method. The present invention provides a quantification method for lipoprotein cholesterol in a test sample containing a lipoprotein optionally using a quantification reagent, the method including adding a phospholipid to the test sample or the quantification reagent. The present invention also provides a quantification reagent for cholesterol in a lipoprotein used in the method of the present invention, the quantification reagent containing a phospholipid. The present invention also provides a quantification kit for lipoprotein cholesterol used in the method of the present invention, the quantification kit containing a phospholipid.

Abstract: Disclosed are a method and reagent of quantifying cholesterol in triglyceride-rich lipoprotein (TRL-C) in a test sample in a more specific manner without requiring laborious operations. The method of quantifying cholesterol in triglyceride-rich lipoprotein (TRL-C) includes the steps of: (1) selectively eliminating cholesterol in lipoproteins other than triglyceride-rich lipoprotein (TRL) by allowing a cholesterol esterase having a molecular weight of more than 50 kDa and a surfactant(s) to act; and (2) quantifying the remaining TRL-C.