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US4728608A
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Bacterial screening system with enhanced shelf life
Assignee: Cambridge Biotech Corp
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Filing: 1985-04-08
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Granted: 1988-03-01
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Expires: 2005-04-08
Abstract
Abstract A tetrazolium-based system for testing for the presence of organisms or cells in a specimen includes in one embodiment a mixture of a substrate and an indicator system, wherein the overall system is buffered to a pH above 8.0, and in a preferred embodiment at about a pH of 9.0 when mixed. The substrate solution and indicator solution are not mixed until shortly before use. The indicator solution is buffered at a pH of approximately 3.3, thereby enhancing the shelf life. The substrate may consist of glucose with at least one amino acid in a buffered solution formulated such that, by mixing equal parts with the indicator solution, a pH above 8, preferably 9.0 results.
Inventors
- 👤 John W. Roberts
- 👤 Karen E. DeBell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:52
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/02; C12Q1/04; C12Q2304/00; C12Q2304/20; C12Q2304/24; Y; Y10; Y10S; Y10S435/00; Y10S435/81
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
139 words
A disposable test system for testing for the presence of bacterial organisms in a specimen, the system consisting essentially of: a buffered substrate solution, for bacterial dehydrogenases in the specimen; and an indicator solution for detecting the presence of the bacterial dehydrogenases in the specimen, including (a) a tetrazolium salt; and (b) phenazine ethosulfate, wherein (i) the indicator solution is buffered to a pH of approximately 3.3, thereby enhancing the shelf life of the indicator solution, (ii) the substrate solution and the indicator solution are not mixed until shortly before use, wherein the shelf-life of the test system is enhanced, and (iii) the substrate solution is buffered to a sufficiently high pH so that the test system when mixed has a pH between 8.8 and 9.2, whereby enhanced test sensitivity is achieved without a resulting loss of test specificity.
Claim 2
Dependent Claim
139 words
A disposable test system for testing for the presence of bacterial organisms in a specimen, the system consisting essentially of: a buffered substrate solution, for bacterial dehydrogenases in the specimen; and an indicator solution for detecting the presence of the bacterial dehydrogenases in the specimen, including (a) a tetrazolium salt; and (b) phenazine ethosulfate, wherein (i) the indicator solution is buffered to a pH of approximately 3.3, thereby enhancing the shelf life of the indicator solution, (ii) the substrate solution and the indicator solution are not mixed until shortly before use, wherein the shelf-life of the test system is enhanced, and (iii) the substrate solution is buffered to a sufficiently high pH so that the test system when mixed has a pH between 8.8 and 9.2, whereby enhanced test sensitivity is achieved without a resulting loss of test specificity.
Claim 3
Dependent Claim
19 words
A test system according to claim 1, wherein the substrate solution comprises glucose and at least one amino acid.
Claim 4
Dependent Claim
26 words
A test system according to claim 1, wherein the substrate solution consists essentially of glucose, serine, glutamic acid Tris base, anhydrous sodium carbonate and deionized water.
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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) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |