Methods and systems for clinical analyte determination by visible and infrared spectroscopy

• US 6,393,310 B1
• Filed: 09/09/1999
• Issued: 05/21/2002
• Est. Priority Date: 09/09/1998
• Status: Expired due to Fees

• Current Assignee: Kuenstner J. Todd
• Original Assignee: Kuenstner J. Todd
• Inventors: Kuenstner, J. Todd
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US09/391,986
• Time in Patent Office: 985 Days
• Field of Search: 600/309-310, 600/322-324, 600/326, 600/328, 356/39-42
• US Class Current: 600/322
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence

Abstract

Noninvasive, in-vivo, methods and system for determining a person'"'"'s relative individual percentages of a plurality of hemoglobin species and for determining a person'"'"'s total hemoglobin concentration, as well as, the concentration of the hemoglobin species which contribute to this total concentration, i.e., oxy-, deoxy-, carboxy-, met- and suf- hemoglobin are described. In a first embodiment, analyte wavelengths are selected in the visible region from 510 nm to 620 nm, with separate analyte wavelengths for each hemoglobin species to determine relative individual percentages. The measurements are then combined in a series of simultaneous equations which are then solved for the concentration of each species and the total concentration of hemoglobin. In a second embodiment, wavelengths in the near infrared region from 650 nm to 1000 nm and derivative spectra are employed to determine total hemoglobin concentration, as well as, the concentration of the hemoglobin species which contribute to this total concentration.

Claims

1. A method for the in-vivo determination of the relative individual percentages of a plurality of hemoglobin species comprising:

generating a spectrophotometric data measurement by

measuring a spectrophotometric property of light at a plurality of wavelengths in capillary bed tissue said plurality of wavelengths ranging from 510 to 620 nm and including;

at least one analyte wavelength for a hemoglobin species;

at least one analyte wavelength for at least a second hemoglobin species;

a first reference wavelength; and

a second reference wavelength;

calculating the difference in the spectrophotometric property at the first reference wavelength and the second reference wavelength to define a difference term;

normalizing the spectrophotometric measurement at each analyte wavelength utilizing the ratio of the spectrophotometric measurement at the analyte wavelength to the difference term; and

determining relative percentages of the hemoglobin species.

2. The method of claim 1 wherein the hemoglobin species is selected from the group consisting of:

oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methehemoglobin.

3. The method of claim 2 wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin.

4. The method of claim 1 wherein a spectrophotometric data measurement is generated at a plurality, n, of analyte wavelengths corresponding to a plurality, n, of hemoglobin species to be measured and the determination of relative percentages includes a multivariate analysis including the solution of n equations having n variables.

5. The method of claim 4 wherein the plurality of analyte wavelengths comprises an analyte wavelength for each of oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, methemoglobin, and sulfhemoglobin.

6. The method of claim 1 wherein the spectrophotometric property is absorbance.

7. The method of claim 1 wherein the spectrophotometric property is reflectance.

8. The method of claim 1 wherein the spectrophotometric property is emission.

9. The method of claim 1 further comprising:

isolating the spectrophotometric measurement due to arterial blood by;

generating a peak spectrophotometric measurement by measuring the absorbance of light at said plurality of wavelengths in capillary bed tissue during the peak of a blood pulsation through the tissue,

generating a trough spectrophotometric measurement by measuring the absorbance of the light at said plurality of wavelengths in capillary bed tissue during the trough of a blood pulsation through the tissue;

subtracting the trough spectrophotometric measurement from the peak spectrophotometric measurement to isolate the spectrophotometric measurement due to arterial blood.