Uric acid assay device with stabilized uricase reagent composition
First Claim
1. An assay device for determination of the presence and concentration of uric acid in a liquid sample comprising:
- a reagent test patch; and
, a working solution applied to the reagent test patch, the working solution comprising an enzyme stabilizer, uricase, a chromogen system, an oxygen acceptor and a buffer that buffers the solution to a pH of 8.5 to 9.5 and has a salt concentration of 1.0 to 2.0M;
wherein the reagent test patch is dried after application of the working solution.
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Abstract
The invention provides an enzyme-based device and process for manufacture of the device in a shelf-stable form. The device consists of a dry phase test strip useful in detecting the presence and concentration of uric acid in a liquid sample (such as urine) and has a stabilized uricase-containing working solution impregnated therein. Methods for manufacturing the device to maintain the stability of the working solution, especially the enzyme components therof, are also described. A method for making the uric acid measurement in one step is also provided, wherein the one step to be performed consists of applying the liquid sample to the test strip of the device.
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Citations
32 Claims
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1. An assay device for determination of the presence and concentration of uric acid in a liquid sample comprising:
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a reagent test patch; and
,a working solution applied to the reagent test patch, the working solution comprising an enzyme stabilizer, uricase, a chromogen system, an oxygen acceptor and a buffer that buffers the solution to a pH of 8.5 to 9.5 and has a salt concentration of 1.0 to 2.0M;
wherein the reagent test patch is dried after application of the working solution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 31, 32)
(a) contacting the reagent test patch with the liquid sample; and
(b) observing whether a change in color occurs on the reagent test patch, wherein a change in color indicates that uric acid is present in the liquid sample.
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32. The method of claim 31, wherein the liquid sample is a urine sample from a mammal.
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12. An assay device for determination of the presence and concentration of uric acid in a liquid sample comprising:
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a reagent test patch; and
,a working solution applied to the reagent test patch, the working solution comprising an enzyme stabilizer, uricase, a chromogen system, an oxygen acceptor and a first buffer that buffers the solution to a pH of 6.5 to 7.5 and has a salt concentration of 50 mM to 2.0M;
wherein the reagent test patch is dried after application of the first working solution, then a second buffer having a pH of 6.5 to 7.5 and a salt concentration greater than the salt concentration of the first buffer is applied to the reagent test patch, which is then dried. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An assay device for determination of the presence and concentration of uric acid in a liquid sample comprising:
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a reagent test patch; and
,a stabilized working solution applied to the reagent test patch, the working solution comprising a sugar, uricase, a chromogen system, an oxygen acceptor and a buffer that buffers the solution to a pH of 8.5 to 9.5 and has a salt concentration of 1.0 to 2.0M;
wherein the reagent test patch is dried after application of the working solution. - View Dependent Claims (26, 27)
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28. An assay device for determination of the presence and concentration of uric acid in a liquid sample comprising:
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a reagent test patch; and
,a working solution applied to the reagent test patch, the working solution comprising uricase, sugar, a chromogen system, an oxygen acceptor and a first buffer that buffers the solution to a pH of 6.5 to 7.5 and has a salt concentration of 50 mM to 2.0M;
wherein the reagent test patch is dried after application of the first working solution, then a second buffer having a pH of 6.5 to 7.5 and a salt concentration greater than the salt concentration of the first buffer is applied to the reagent test patch, which is then dried. - View Dependent Claims (29, 30)
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Specification