Turbidimetric immunoassay for assessing human Cystatin C
AssigneeGentian AS
InventorsKathrin Sunde, Tom Nilsen
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Abstract
There is a demand for improved turbidimetric immunoassays for human Cystatin C in biological samples, especially in human clinical samples of body fluids. The present invention provides a turbidimetric immunoassay method and reagent set enabling measurement of human Cystatin C by turbidimetric methods, resulting in a surprisingly stronger and faster turbidimetric signal than in the present state of the art. The increased and faster signal is accomplished by the use of new reagents and compositions, and enables shorter assay times and kinetic reading with a stronger signal, improving overall assay speed and quality. Improved robustness to lipid interference and improved linearity is achieved.
Claims24
A method of turbidimetric immunoassay for assessing human Cystatin C in a human body liquid sample comprising
- a) forming an assay mixture by contacting said sample with a nanoparticle-antibody conjugate, comprising nanoparticles suitable for turbidimetric measurement, wherein said nanoparticles are coated with a shell of proteinaceous material comprising anti-human Cystatin C antibodies or antigen binding fragments thereof, to bind said Cystatin C, wherein said coated nanoparticles have a median diameter in the range of more than 58 up to 200 nm, and
- b) assessing the human Cystatin C content by measuring the change in turbidity of said mixture,
- wherein the coating is such that said nanoparticles are coated with about 5 to 35% of antibody binding to human Cystatin C per total weight of the nanoparticle-antibody conjugate.
Dependencies are inferred from the claim text.