Method of measuring lipid in specific lipoprotein

A method for assaying HDL cholesterol in a sample, comprising:

• determining the specificity of an assay for HDL cholesterol, and
• assaying HDL cholesterol using said assay;
• wherein at least one polycyclic polyoxyalkylene derivative having an HLB of 14.1 to 18 and being selected from the group consisting of polyoxyalkylene polycyclic phenyl ether, polyoxyethylene tribenzylphenyl ether, polyoxyalkylene polystyrylphenyl ether;
• polyoxyalkylene phenylphenol ether, polyoxyalkylene polystyrylphenyl ether condensate, polyoxyalkylene alkylphenyl ether condensate, polyoxyalkylene styrylated phenyl ether, and polyoxyalkylene allylphenyl ether is employed at least in the specificity determining step.

A method for determining the amount of HDL cholesterol in a sample, comprising:

• determining the specificity of an assay for HDL cholesterol by pretreating lipids other than HDL cholesterol in a biological sample to obtain a pretreated reaction mixture containing HDL cholesterol,
• reacting the HDL cholesterol in said pretreated reaction mixture with an enzyme that releases cholesterol from said HDL cholesterol, and
• assaying the cholesterol,
• thereby determining the amount of HDL cholesterol in said biological sample;
• wherein at least the determining the specificity of the assay is performed in the presence of at least one nonionic polycyclic polyoxyalkylene surfactant having an HLB of 14.1 to 18 selected from the group consisting of polyoxyalkylene polycyclic phenyl ether, polyoxyethylene tribenzylphenyl ether, polyoxyalkylene polystyrylphenyl ether, polyoxyalkylene phenylphenol ether, polyoxyalkylene polystyrylphenyl ether condensate, polyoxyalkylene alkylphenyl ether condensate, polyoxyalkylene styrylated phenyl ether, and polyoxyalkylene allylphenyl ether.