Patent US5385846A successfully refreshed from Google Patents.
US5385846A
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Biosensor and method for hematocrit determination
Assignee: Roche Diabetes Care Inc
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Filing: 1993-06-03
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Granted: 1995-01-31
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Expires: 2013-06-03
Abstract
Abstract A biosensor and method for determining the hematocrit level of a whole blood sample using electrochemistry. The biosensor includes working and counter electrodes. A porous membrane is impregnated with an electroactive compound and is spatially displaced from the surface of the electrodes. When a whole blood sample is applied to the porous substrate, a mixture of the electroactive compound and the blood is formed. The mixture settles on the electrodes and a potential difference is applied sufficient to oxidize or reduce the electroactive compound and generate a current. This current can be measured and correlated to hematocrit level.
Inventors
- 👤 Lance S. Kuhn
- 👤 Mary L. Ochs
- 👤 Gilbert C. Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:04
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/483; G01N33/487; G01N33/49
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
127 words
An apparatus for measuring the hematocrit level of a blood sample, comprising: (a) a first insulating substrate; (b) working and counter electrodes affixed to the first insulating substrate; (c) a second insulating substrate, which overlays the working and counter electrodes, has a window for exposing a portion of the working and counter electrodes, and has a cut out portion at one end to allow contact between the electrodes and a meter and a power source; and (d) a porous substrate, which is impregnated with an electroactive compound, overlays the window, and is spatially displaced from the working and counter electrodes so that there is an empty space between the working and counter electrodes and the porous substrate prior to addition of the blood sample to the apparatus.
Claim 2
Independent Claim
127 words
An apparatus for measuring the hematocrit level of a blood sample, comprising: (a) a first insulating substrate; (b) working and counter electrodes affixed to the first insulating substrate; (c) a second insulating substrate, which overlays the working and counter electrodes, has a window for exposing a portion of the working and counter electrodes, and has a cut out portion at one end to allow contact between the electrodes and a meter and a power source; and (d) a porous substrate, which is impregnated with an electroactive compound, overlays the window, and is spatially displaced from the working and counter electrodes so that there is an empty space between the working and counter electrodes and the porous substrate prior to addition of the blood sample to the apparatus.
Claim 3
Dependent Claim
25 words
The apparatus of claim 1, wherein the electrically conducting material of the working and counter electrodes is palladium, platinum, gold, silver, titanium, copper, or carbon.
Claim 4
Dependent Claim
23 words
The apparatus of claim 2, wherein the working and counter electrodes are made of the same material and are substantially the same size.
Claim 5
Dependent Claim
18 words
The apparatus of claim 2, wherein the porous substrate is a mesh, a membrane, or a porous film.
Claim 6
Dependent Claim
13 words
The apparatus of claim 3, wherein the porous substrate is a polyester mesh.
Claim 7
Dependent Claim
14 words
The apparatus of claim 5, further comprising a cover mesh overlaying the porous substrate.
Claim 8
Dependent Claim
116 words
The apparatus of claim 5, further comprising: (e) a power source in electrical connection with the working and counter electrodes and capable of supplying an electrical potential difference between the working and counter electrodes sufficient to cause diffusion limited electrooxidation of a reduced form of the electroactive compound or diffusion limited electroreduction of an oxidized form of the electroactive compound at a surface of the working electrode; and (f) a meter in electrical connection with the working and counter electrodes and capable of measuring the diffusion limited current produced by the oxidation of the reduced form of the electroactive compound or the reduction of the oxidized form of the electroactive compound at the working electrode surface.
Claim 9
Dependent Claim
42 words
The apparatus of claim 7, wherein the cover mesh is impregnated with a surfactant or surface active agent in sufficient amount to aid in drawing the electroactive compound into the porous substrate when a blood sample is added to the cover mesh.
Claim 10
Dependent Claim
27 words
The apparatus of claim 8, wherein the porous substrate is impregnated with a reagent, the reagent comprising a reversible electroactive compound, an electrolyte, and a microcrystalline material.
Claim 11
Dependent Claim
29 words
The apparatus of claim 9, wherein the oxidized form of the electroactive compound is potassium hexacyanoferrate (III) and the reduced form of the electroactive compound is potassium hexacyanoferrate (II).
Claim 12
Dependent Claim
37 words
The apparatus of claim 10, wherein the porous substrate is also impregnated with a surfactant or surface active agent in sufficient amount to aid in spreading the electroactive compound throughout the porous substrate when manufacturing the biosensor.
Claim 13
Dependent Claim
96 words
A method of measuring the hematocrit level of a blood sample, comprising: (a) adding the blood sample to the porous substrate of the apparatus of claim 1, thereby forming a mixture of the electroactive compound and the blood sample, the mixture being deposited on a surface of the electrodes; (b) applying a potential difference between the working and counter electrodes that is sufficient to oxidize or reduce the electroactive compound in the mixture at the surface of the working electrode, thereby generating a current; and (c) measuring the current and correlating the current to hematocrit level.
Claim 14
Dependent Claim
25 words
The method of claim 12, wherein the electrically conducting material of the working and counter electrodes is palladium, platinum, gold, silver, titanium, copper, or carbon.
Claim 15
Dependent Claim
20 words
The method of claim 13, wherein the electrodes are made of the same material and are substantially the same size.
Claim 16
Dependent Claim
13 words
The method of claim 13, wherein the porous substrate is a polyester mesh.
Claim 17
Dependent Claim
102 words
A method of measuring the hematocrit level of a blood sample, comprising: (a) adding the blood sample to the porous substrate of the apparatus of claim 2, thereby forming an electroactive compound and blood sample mixture, which is deposited on a surface of the electrodes; (b) applying a potential difference between the electrodes that is sufficient to oxidize the electroactive compound in the mixture at the surface of one electrode and to reduce the electroactive compound in the mixture at the surface of the other electrode, thereby generating a current; and (c) measuring the current and correlating the current to hematocrit level.
Claim 18
Dependent Claim
19 words
The method of claim 16, wherein the porous substrate is a polyester mesh, a membrane, or a porous film.
Claim 19
Dependent Claim
29 words
The method of claim 17, wherein an oxidized form of the electroactive compound is potassium hexacyanoferrate (III) and a reduced form of the electroactive compound is potassium hexacyanoferrate (II).
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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) | 1998-01-30 | 1998-08-01 | 1999-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-30 | 2002-08-01 | 2003-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-30 | 2006-08-01 | 2007-01-31 | $7700.00 | Window Closed / Lapsed |