US4234313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device and method for quantitative uric acid testing
Assignee: Murex Diagnostics Inc
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Filing: 1978-06-05
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Granted: 1980-11-18
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Expires: 1998-06-05
Abstract
Abstract A testing composition provided in test-strip form, which comprises a predetermined amount of a colored indicator on a solid, inert support, the indicator being responsive to the material being tested in such a manner it loses its color in a direct proportion to the amount of material present. The testing composition may be provided with a semipermeable membrane to prevent the deposition of suspended particles on the composition. Also provided is a method of determining the minimum or maximum level of a material, for instance uric acid, in fluids using the testing composition and comparing it with a comparator strip.
Inventors
- 👤 Douglas E. Faulkner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:41
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; G01N33/521; G01N33/523; Y; Y10; Y10T; Y10T436/00; Y10T436/14; Y10T436/145555; Y10T436/147777; Y10T436/148888
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
159 words
A quantitative uric acid testing device comprising: (a) a solid, physically and chemically inert, support in the form of a strip; (b) a coloured indicator means for comparing the concentration of uric acid in an aqueous test sample with a preselected concentration limit of uric acid within the range of 5 to 9 mg/100 ml sample, said means being capable of being reduced into a colourless form and being provided on said support in an amount adjusted so as to be equivalent to said preselcted concentration limit so that when said support is saturated with the test sample, said indicator completely loses its colour if the uric acid concentration in said sample is equal to or higher than said preselected concentration limit of uric acid, the colour loss being in consequence of other than a change in pH; and (c) protective means for preventing particles suspended in said test sample coming into contact with said support and said indicator.
Claim 2
Dependent Claim
159 words
A quantitative uric acid testing device comprising: (a) a solid, physically and chemically inert, support in the form of a strip; (b) a coloured indicator means for comparing the concentration of uric acid in an aqueous test sample with a preselected concentration limit of uric acid within the range of 5 to 9 mg/100 ml sample, said means being capable of being reduced into a colourless form and being provided on said support in an amount adjusted so as to be equivalent to said preselcted concentration limit so that when said support is saturated with the test sample, said indicator completely loses its colour if the uric acid concentration in said sample is equal to or higher than said preselected concentration limit of uric acid, the colour loss being in consequence of other than a change in pH; and (c) protective means for preventing particles suspended in said test sample coming into contact with said support and said indicator.
Claim 3
Dependent Claim
38 words
A testing device as claimed in claim 1 which is combined with a comparator which is similarly composed to the main testing device in all respects except that it contains none or a smaller amount of the indicator.
Claim 4
Dependent Claim
18 words
A testing device as claimed in claim 1 wherein said protective means comprises at least one semi-permeable membrane.
Claim 5
Dependent Claim
15 words
A testing device as claimed in claim 3 wherein the semi-permeable membrane is of nitrocellose.
Claim 6
Dependent Claim
21 words
A testing device as claimed in claim 3 or claim 4 wherein an alkaline agent is incorporated into the semi-permeable membrane.
Claim 7
Dependent Claim
17 words
A testing device as claimed in claim 5 wherein the alkaline agent is an alkali metal carbonate.
Claim 8
Dependent Claim
25 words
A testing device as claimed in claim 6 wherein the concentration of the alkali metal carbonate is from 1.88×10 -2 M to 4.5×10 -2 M.
Claim 9
Dependent Claim
28 words
A testing device as claimed in claim 1 wherein the coloured indicator is a combination of an iodine source and an iodine indicator, together with an iodine solubilizer.
Claim 10
Dependent Claim
18 words
A testing device as claimed in claim 1 or 8 wherein the support is a glass fibre filter.
Claim 11
Dependent Claim
18 words
A testing device as claimed in claim 1 or 8 wherein the support is an inert filter paper.
Claim 12
Dependent Claim
58 words
A method for comparing with a selected concentration limit, the concentration of uric acid in a test sample of test fluid comprising applying a sample of test fluid to the testing device as claimed in claim 1 or 8, allowing the test fluid to react with the testing device, and observing the presence or absence of colour reaction.
Claim 13
Dependent Claim
20 words
A testing device as claimed in claim 1 or 8 wherein the support is attached to an impervious backing sheet.
Claim 14
Dependent Claim
16 words
A testing device as claimed in claim 12 wherein the backing sheet is of polyvinyl chloride.
Claim 15
Dependent Claim
17 words
A testing device as claimed in claim 8 wherein the iodine source is a solution of iodine.
Claim 16
Dependent Claim
24 words
A testing device as claimed in claim 8 wherein the concentration of the iodine source is from 2.0×10 -3 N to 2.7×10 -3 N.
Claim 17
Dependent Claim
37 words
A testing device as claimed in claim 8 wherein the iodine indicator is soluble starch, amylose, amylopectin, dextrin, α-naphthaflavone, polyvinylpyrrollidone, polyvinyl alcohol, glycogen, sodium starch glycollate or other polysaccharides which give a satisfactory colour reaction with iodine.
Claim 18
Dependent Claim
20 words
A testing device as claimed in claim 8 wherein the concentration of the iodine solubilizer is from 6 to 12%.
Claim 19
Dependent Claim
16 words
A testing device as claimed in claim 8 wherein the iodine source is a complex one.
Claim 20
Dependent Claim
16 words
A testing device as claimed in claim 18 wherein the complex iodine source is an iodophor.
Claim 21
Dependent Claim
15 words
A testing device as claimed in claim 8 wherein the iodine solubilizer is an iodide.
Claim 22
Dependent Claim
14 words
A testing device as claimed in claim 20 wherein the iodide is potassium iodide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |