US5222495A
Expired / Lapsed
US
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Non-invasive blood analysis by near infrared absorption measurements using two closely spaced wavelengths
Assignee: DIABETES CONTROL & CARE TECHNOLOGY Inc
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Filing: 1992-08-14
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Granted: 1993-06-29
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Expires: 2012-08-14
Abstract
Abstract Systems and methods for non-invasive blood analysis are disclosed in which blood is illuminated at a plurality of discrete wavelengths selected from the near infrared spectrum. Measurements of the intensity of transmitted or reflected light at such wavelengths are taken, and an analysis of transmittance or reflectance ratios for various wavelengths is performed. Changes in the ratios can be correlated with specific near infrared (IR) absorption peak for the analyte which varies with concentration of the analyte (the data wavelength) and the a second (reference) wavelength being sufficiently removed from the first so that measurements of light absorption at this second wavelength are relatively insensitive to the concentration of the analyte and yet the second wavelength is sufficiently close to the first wavelength to minimize interference from scattering effects and the like. Typically, the window bracketing these closely spaced wavelengths will be less than about 300 nm and preferably less than about 60 nm wide and, in some instances, more preferably less than about 30 nm wide.
Inventors
- 👤 Richard H. Clarke
- 👤 Qian Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:36
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/145; A61B5/1455; A61B5/14532; A61B2562/00; A61B2562/02; A61B2562/0233; A61B2562/04; A61B2562/043
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
105 words
A blood-analyte detection apparatus comprising: infrared illumination means for non-invasively illuminating an in vivo blood sample in a patient at least two wavelengths in the near infrared spectrum; detector means for non-invasively measuring light absorbed by said sample at least a first data wavelength and a second reference wavelength, and for converting said detected light into electrical signals, said signals being indicative of the intensity of said detected light at each wavelength; the detector means further characterized as measuring light absorption at two closely-spaced wavelengths said first and second wavelengths spaced by less than about 60 nanometers in order to minimize inference from extraneous factors.
Claim 2
Dependent Claim
105 words
A blood-analyte detection apparatus comprising: infrared illumination means for non-invasively illuminating an in vivo blood sample in a patient at least two wavelengths in the near infrared spectrum; detector means for non-invasively measuring light absorbed by said sample at least a first data wavelength and a second reference wavelength, and for converting said detected light into electrical signals, said signals being indicative of the intensity of said detected light at each wavelength; the detector means further characterized as measuring light absorption at two closely-spaced wavelengths said first and second wavelengths spaced by less than about 60 nanometers in order to minimize inference from extraneous factors.
Claim 3
Dependent Claim
13 words
The apparatus of claim 1 wherein the illumination means is broadband infrared emitter.
Claim 4
Dependent Claim
27 words
The apparatus of claim 1 wherein the illumination means comprises a plurality of discrete IR radiation sources emitting light at different wavelengths in the near infrared spectrum.
Claim 5
Dependent Claim
28 words
The apparatus of claim 1 wherein the illumination means emits at least two wavelengths of infrared radiation within a spectrum ranging from about 1000 to about 2500 nm.
Claim 6
Dependent Claim
28 words
The apparatus of claim 1 wherein the illumination means emits at least two wavelengths of infrared radiation within a spectrum ranging from about 1300 to about 2300 nm.
Claim 7
Dependent Claim
28 words
The apparatus of claim 1 wherein the illumination means emits at least two wavelengths of infrared radiation within a spectrum ranging from about 1500 to about 1800 nm.
Claim 8
Dependent Claim
18 words
The apparatus of claim 1 wherein said detector means detects the reflectance of said light upon said sample.
Claim 9
Dependent Claim
18 words
The apparatus of claim 1 wherein said detector means detects the transmittance of said light by said sample.
Claim 10
Dependent Claim
16 words
The apparatus of claim 1 wherein the detector further comprises a plurality of wavelength specific filters.
Claim 11
Dependent Claim
19 words
The apparatus of claim 1 wherein said first and second wavelengths are separated by less than about 30 nm.
Claim 12
Dependent Claim
34 words
The apparatus of claim 1 wherein one of said wavelengths is about 1600 nm for generating an analyte data signal and another of said wavelengths is about 1630-1660 for generation of a reference signal.
Claim 13
Dependent Claim
19 words
The apparatus of claim 1 wherein one of said wavelengths is about 1300 nm for generating a reference signal.
Claim 14
Dependent Claim
57 words
The apparatus of claim 1 wherein the apparatus further comprises an analyzing means for receiving and comparing said electrical signals to derive a detection ratio for at least two of said wavelengths, such that said ratio can be compared with predetermined values associated with known blood-analyte concentrations so as to detect the analyte level in said sample.
Claim 15
Independent Claim
124 words
A method for detecting an analyte in a blood sample, comprising the steps of: illuminating a source of blood non-invasively through the tissue of a subject at a plurality of wavelengths within a narrow window selected in the near infrared spectrum; detecting light effected by said blood and converting said detected light into electrical signals indicative of the intensity of said effected light at a plurality of wavelengths selected from the near infrared spectrum, including a first data wavelength and a second reference wavelength separated by less than about 60 nanometers; analyzing said electrical signals to derive a ratio for at least two of said wavelengths; and comparing said ratio to a predetermined value to detect the presence of an analyte in said blood.
Claim 16
Independent Claim
124 words
A method for detecting an analyte in a blood sample, comprising the steps of: illuminating a source of blood non-invasively through the tissue of a subject at a plurality of wavelengths within a narrow window selected in the near infrared spectrum; detecting light effected by said blood and converting said detected light into electrical signals indicative of the intensity of said effected light at a plurality of wavelengths selected from the near infrared spectrum, including a first data wavelength and a second reference wavelength separated by less than about 60 nanometers; analyzing said electrical signals to derive a ratio for at least two of said wavelengths; and comparing said ratio to a predetermined value to detect the presence of an analyte in said blood.
Claim 17
Dependent Claim
19 words
The method of claim 14 wherein said first and second wavelengths are separated by less than about 30 nm.
Claim 18
Dependent Claim
18 words
The method of claim 14 wherein said detected light is a measure of the reflectance of said blood.
Claim 19
Dependent Claim
18 words
The method of claim 14 wherein said detected light is a measure of the transmittance of said blood.
Claim 20
Dependent Claim
10 words
The method of claim 14 wherein said tissue is skin.
Claim 21
Dependent Claim
12 words
The method of claim 14 wherein said tissue is in a nailbed.
Claim 22
Dependent Claim
11 words
The method of claim 14 wherein said tissue includes a vein.
References Cited (Backward Citations)
US3463142A
Cited
US3638640A
Cited
US3958560A
Cited
US4014321A
Cited
US4169676A
Cited
US4202339A
Cited
GB2075668A
Cited
US4223680A
Cited
GB2033575A
Cited
US4350163A
Cited
US4408880A
Cited
EP0160768B1
Cited
US4655225A
Cited
US4704029A
Cited
US4714080A
Cited
US4840179A
Cited
EP0282210A1
Cited
EP0282234A1
Cited
US4785814A
Cited
US4796636A
Cited
US4854699A
Cited
US4882492A
Cited
US4901728A
Cited
WO1990007905A1
Cited
US5086229A
Cited
US4975581A
Cited
EP0404562A2
Cited
US5007423A
Cited
US5070874A
Cited
WO1991011136A1
Cited
US5054487A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-28 | 1996-12-28 | 1997-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-28 | 2000-12-28 | 2001-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-28 | 2004-12-28 | 2005-06-29 | $7700.00 | Window Closed / Lapsed |