The invention provides an enzymatic method for measuring the concentration of one or more analytes in the plasma portion of a blood derived sample, containing a first and a second component, where said second component interferes with the measurement of said first component. The method includes: i) diluting the sample with a reagent mixture; ii) substantially removing blood cells; iii) using a reagent which serves to temporarily prevent reaction of the second component, to generate a blocked second component; iv) causing the selective reaction of a constituent of each analyte to directly or indirectly generate detectable reaction products, where one of the analytes is the first component; v) monitoring the detectable reaction product or products; vi) relating an amount of the detectable product or products and/or a rate of formation of the detectable product or products to the concentration of each analyte, where the concentration of at least the first component is related to a corresponding detectable reaction product by means of estimating an un-measurable (fictive) endpoint. Step iii) may be carried out at any stage up to and including step iv) but before steps v) or vi). The reagent of step iii) may be applied to the sample separately or may be included in a reagent mixture during steps i) or iv). A corresponding kit is also provided.

The invention provides an enzymatic method for measuring the concentration of one or more analytes in the plasma portion of a blood derived sample, containing a first and a second component, where said second component interferes with the measurement of said first component. The method includes: i) diluting the sample with a reagent mixture; ii) substantially removing blood cells; iii) using a reagent which serves to temporarily prevent reaction of the second component, to generate a blocked second component; iv) causing the selective reaction of a constituent of each analyte to directly or indirectly generate detectable reaction products, where one of the analytes is the first component; v) monitoring the detectable reaction product or products; vi) relating an amount of the detectable product or products and/or a rate of formation of the detectable product or products to the concentration of each analyte, where the concentration of at least the first component is related to a corresponding detectable reaction product by means of estimating an un-measurable (fictive) endpoint. Step iii) may be carried out at any stage up to and including step iv) but before steps v) or vi). The reagent of step iii) may be applied to the sample separately or may be included in a reagent mixture during steps i) or iv). A corresponding kit is also provided.

Reagents, assays, methods, kits, devices, and systems for rapid measurement of cholesterol and cholesterol sub-fractions from a blood sample are provided. Total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol can be measured in a single assay using kinetic measurements, under conditions in which cholesterol sub-species are converted to a detectable product at distinct rates. The detectable product is measured at different times after assay initiation. A lipase, cholesterol esterase, cholesterol oxidase and a peroxidase may be used together to produce colored product in amounts directly proportional to the quantity of cholesterol converted. Methods for calculating very-low density lipoprotein cholesterol levels by further including triglyceride measurements are disclosed. Assays may be performed in a single reaction mixture, allowing more accurate and precise cholesterol determinations, including ratios of cholesterol sub-fractions to total cholesterol, at less expense, than would be expected by performing several different assays in different reaction mixtures.

Reagents, assays, methods, kits, devices, and systems for rapid measurement of cholesterol and cholesterol sub-fractions from a blood sample are provided. Total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol can be measured in a single assay using kinetic measurements, under conditions in which cholesterol sub-species are converted to a detectable product at distinct rates. The detectable product is measured at different times after assay initiation. A lipase, cholesterol esterase, cholesterol oxidase and a peroxidase may be used together to produce colored product in amounts directly proportional to the quantity of cholesterol converted. Methods for calculating very-low density lipoprotein cholesterol levels by further including triglyceride measurements are disclosed. Assays may be performed in a single reaction mixture, allowing more accurate and precise cholesterol determinations, including ratios of cholesterol sub-fractions to total cholesterol, at less expense, than would be expected by performing several different assays in different reaction mixtures.

The invention provides an enzymatic method for measuring the concentration of one or more analytes in the plasma portion of a blood derived sample, containing a first and a second component, where said second component interferes with the measurement of said first component. The method includes: i) diluting the sample with a reagent mixture; ii) substantially removing blood cells; iii) using a reagent which serves to temporarily prevent reaction of the second component, to generate a blocked second component; iv) causing the selective reaction of a constituent of each analyte to directly or indirectly generate detectable reaction products, where one of the analytes is the first component; v) monitoring the detectable reaction product or products; vi) relating an amount of the detectable product or products and/or a rate of formation of the detectable product or products to the concentration of each analyte, where the concentration of at least the first component is related to a corresponding detectable reaction product by means of estimating an un-measurable (fictive) endpoint. Step iii) may be carried out at any stage up to and including step iv) but before steps v) or vi). The reagent of step iii) may be applied to the sample separately or may be included in a reagent mixture during steps i) or iv). A corresponding kit is also provided.

The invention provides an enzymatic method for measuring the concentration of one or more analytes in the plasma portion of a blood derived sample, containing a first and a second component, where said second component interferes with the measurement of said first component. The method includes: i) diluting the sample with a reagent mixture; ii) substantially removing blood cells; iii) using a reagent which serves to temporarily prevent reaction of the second component, to generate a blocked second component; iv) causing the selective reaction of a constituent of each analyte to directly or indirectly generate detectable reaction products, where one of the analytes is the first component; v) monitoring the detectable reaction product or products; vi) relating an amount of the detectable product or products and/or a rate of formation of the detectable product or products to the concentration of each analyte, where the concentration of at least the first component is related to a corresponding detectable reaction product by means of estimating an un-measurable (fictive) endpoint. Step iii) may be carried out at any stage up to and including step iv) but before steps v) or vi). The reagent of step iii) may be applied to the sample separately or may be included in a reagent mixture during steps i) or iv). A corresponding kit is also provided.

The present invention provides a measuring method for at least one of a kinase forward reaction substrate, a phosphorylated product thereof, and a precursor thereof, and includes a step of conducting an enzymatic cycling reaction by bringing at least a kinase, a first nucleotide coenzyme of the kinase, and a second nucleotide coenzyme having a different nucleoside moiety from the first nucleotide coenzyme into contact with a sample; a step of detecting a signal corresponding to a change of at least one of the first nucleotide coenzyme and a conversion product thereof, and the second nucleotide coenzyme and a conversion product thereof; and (3) a step of calculating, on the basis of the detected change of the signal, an amount of the kinase forward reaction substrate and/or the phosphorylated product thereof contained in the sample.

The present invention provides a measuring method for at least one of a kinase forward reaction substrate, a phosphorylated product thereof, and a precursor thereof, and includes a step of conducting an enzymatic cycling reaction by bringing at least a kinase, a first nucleotide coenzyme of the kinase, and a second nucleotide coenzyme having a different nucleoside moiety from the first nucleotide coenzyme into contact with a sample; a step of detecting a signal corresponding to a change of at least one of the first nucleotide coenzyme and a conversion product thereof, and the second nucleotide coenzyme and a conversion product thereof; and (3) a step of calculating, on the basis of the detected change of the signal, an amount of the kinase forward reaction substrate and/or the phosphorylated product thereof contained in the sample.

A method of lipid assay characterized by assaying the lipids contained in a blood component in the presence of an organic silicon compound. The method can cause specific conditions for direct methods while satisfying requirements such as no influence on precision of assay, no burden on assay apparatus, and easy availability.

Disclosed is a method for selectively eliminating triglycerides in lipoproteins other than low density lipoprotein, which method allows one to provide a method for directly and differentially quantifying LDL-TG in a sample with excellent simplicity, specificity and accuracy using an automated analyzer or the like without performing a laborious operation of pretreatment such as centrifugation or electrophoresis. The method for eliminating triglycerides in lipoproteins other than low density lipoproteins includes allowing lipoprotein lipase, cholesterol esterase, glycerol kinase and glycerol-3-phosphate oxidase to act on a sample in the presence of a surfactant that acts on lipoproteins other than low density lipoprotein and/or a surfactant having LDL-protecting action, and eliminating hydrogen peroxide produced thereby.