Abstract: A compound is disclosed herein which is water soluble and is useful in assay procedures for measuring serum cholesterol. In one embodiment, the compound comprises a cholesterol ester having the general formula R.sub.1 --R.sub.2 --[Cholesterol Base], in which R.sub.1 is a water soluble, nonionic surfactant and R.sub.2 is a dicarboxyl group bonded by ester linkages to R.sub.1 and to the cholesterol. In an alternate embodiment the compound comprises a pregnenolone derivative having the general formula R.sub.3 --[Pregnenolone Base]--R.sub.4. A compound in accordance with the present invention is useful by itself or in combination with blood serum as a standard or reference material for cholesterol assay procedues.

Abstract: A lipoprotein diluent useful in the preparation of a standard or reference material for assay procedures which comprises a stabilized aqueous solution of turbidity-potential lipoproteins. The solution contains a preservative including a polyhydroxy cryoprotective agent and/or an antibiotic, and may be used directly as a cholesterol or triglyceride standard or control. The solution may also include other stable components but is free from lipoprotein-degrading enzymes. In accordance with the method of the present invention, a standard or reference material is prepared by adding a diluent containing turbidity-potential lipoproteins to a lyophilized serum base, which contains enzymes.

Abstract: A compound is disclosed herein which is water soluble and is useful in assay procedures for measuring serum cholesterol. In one embodiment, the compound comprises a cholesterol ester having the general formula R.sub.1 -R.sub.2 -[Cholesterol Base], in which R.sub.1 is a water soluble, nonionic surfactant and R.sub.2 is a dicarboxyl group bonded by ester linkages to R.sub.1 and to the cholesterol. In an alternate embodiment the compound comprises a pregnenolone derivative having the general formula R.sub.3 -[Pregnenolone Base]-R.sub.4. A compound in accordance with the present invention is useful by itself or in combination with blood serum as a standard or reference material for cholesterol assay procedures.

Abstract: A stable optically clear serum is prepared for use in the preparation of standards and quality control reference material for the assay of human serum components. In one aspect of the present invention, high density lipoproteins isolated from human blood serum are added to substantially human serum to produce a standard or reference material. A second aspect of the present invention involves the addition of isolated, non-primate lipoproteins to substantially human serum. The serum prepared as disclosed has good optical clarity upon lyophilization and reconstitution with aqueous media. Alternatively, the isolated lipoproteins are added in an aqueous diluent to lyophilized human serum.

Abstract: Methods and preparations which function to reduce the turbidity normally associated with triglyceride standards. A method is disclosed of preparing serum suitable for use as a triglyceride standard in which the triglyceride level normally present in the serum is reduced and glycerides of fatty acids having from 5 to 10 carbon atoms are added to the serum. A suitable surfactant for emulsifying the triglycerides is added, the surfactant being an alkylphenoxypolyethoxyethanol having 6 to 10 ethoxy groups. The serum is then lyophilized or frozen and upon reconstitution or thawing, virtually no turbidity exists.

Abstract: A stable optically clear serum is prepared for use in the preparation of standards and quality control reference material for the assay of human serum components. Prebeta lipoproteins, beta lipoproteins and chylomicrons are removed from human serum by specific precipitation. The serum resulting from the process disclosed retains its optical clarity upon freezing, lyophilization and reconstitution with aqueous media. Bovine lipoproteins are added to restore desired levels of cholesterol and triglycerides.