US4529708A
Expired / Lapsed
US
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Assay for the determination of creatinine
Assignee: INDIANA DEVELOPMENT FINANCE AUTHORITY
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Filing: 1983-04-07
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Granted: 1985-07-16
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Expires: 2003-04-07
Abstract
Abstract An improved colorimetric assay method and reagent composition for the quantitative determination of creatinine in biological fluid specimens in the presence of protein, in which the specimen is reacted directly with an alkaline picrate reagent composition which contains an iron chelator, preferably ethylenediaminetetraacetic acid, thereby significantly suppressing interference from bilirubin and improving reagent stability.
Inventors
- 👤 Thomas W. Stephens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:10
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/70; Y; Y10; Y10T; Y10T436/00; Y10T436/14; Y10T436/145555; Y10T436/147777; Y10T436/25; Y10T436/25125
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
66 words
A method for the determination of creatinine in a protein-containing fluid, comprising the steps of: (a) combining a sample of said protein-containing fluid with a reagent to form a reaction mixture, said reagent comprising: (i) an alkalinizing agent, (ii) picrate, and (iii) a substance which binds iron in an amount sufficient to suppress interference from bilirubin; and (b) optically measuring the change in said reaction mixture.
Claim 2
Independent Claim
66 words
A method for the determination of creatinine in a protein-containing fluid, comprising the steps of: (a) combining a sample of said protein-containing fluid with a reagent to form a reaction mixture, said reagent comprising: (i) an alkalinizing agent, (ii) picrate, and (iii) a substance which binds iron in an amount sufficient to suppress interference from bilirubin; and (b) optically measuring the change in said reaction mixture.
Claim 3
Dependent Claim
32 words
A method as recited in claim 1, wherein the substance which binds iron is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), N-hydroxyethylethylenediaminetetraacetic acid (HEDTA), and ethyleneglycol-bis (β-amino-ethyl ether)-N,N'-tetraacetic acid (EGTA).
Claim 4
Dependent Claim
24 words
A method as recited in claim 2, wherein the amount of the substance which binds iron is at least about 0.5 millimoles per liter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-15 | 1989-01-14 | 1989-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-15 | 1993-01-14 | 1993-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-15 | 1997-01-14 | 1997-07-16 | $7700.00 | Window Closed / Lapsed |