Method of sample control and calibration adjustment for use with a noninvasive analyzer

• US 7,383,069 B2
• Filed: 05/18/2004
• Issued: 06/03/2008
• Est. Priority Date: 08/14/1997
• Status: Expired due to Fees

• Current Assignee: GLT Acquisition Corporation
• Original Assignee: Sensys Medical, Inc. (Sensys Medical Limited)
• Inventors: Ruchti, Timothy L., Hazen, Kevin H., Blank, Thomas B.
• Primary Examiner(s): Winakur; Eric F.
• Assistant Examiner(s): Berhanu; Etsub D
• Application Number:
  US10/849,422
• Publication Number:
  US 20050014997A1
• Time in Patent Office: 1,477 Days
• Field of Search: 600/316, 600/331, 600/344, 250/339.09
• US Class Current: 600/331
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/359 using near infrared light

Abstract

A method and apparatus for easing the use of an optically based noninvasive analyzer is presented. More particularly, a simplified algorithm is used that removes the daily requirement of collecting and using a noninvasive spectrum to update a calibration model. In another embodiment, a guide is used to substantially reduce variation in sample probe placement in relation to a skin tissue sampling site, resulting in the ability to maintain calibration performance with the use of a reference analyte concentration, with or without the use of a reference spectrum collected nearby in time.

Claims

1. A noninvasive method for estimating a biological attribute concentration in human tissue of a tested subject, comprising the steps of:

generating a model used for estimating a current or past value, wherein said step of generating uses noninvasive spectra and associated reference concentrations;

adjusting said model with at least one direct reference measurement and without use of a corresponding reference spectrum;

collecting at least one noninvasive spectrum of said tissue of said tested subject with an analyzer;

estimating said biological attribute of said specific subject using said adjusted model; and

displaying said estimated biological attribute.

2. The method of claim 1, further comprising a guide wherein said guide replaceably couples said analyzer to said human tissue.

3. A noninvasive method for measuring a biological attribute of human tissue of a tested subject, comprising the steps of:

providing an apparatus for measuring light throughput, said apparatus comprising an energy source emitting infrared energy at multiple wavelengths, an input element, an output element, and a spectrum analyzer;

coupling said input and output elements to said human tissue;

irradiating said tissue through said input element with multiple wavelengths of infrared energy with resulting absorption of at least some of said wavelengths;

collecting at least a portion of the non-absorbed infrared energy with said output element;

determining the intensities of said infrared energy;

generating a model used for estimating a current or past value, wherein said step of generating uses calibration noninvasive spectra and calibration reference concentrations;

adjusting said model with at least one direct reference measurement and without use of a corresponding reference spectrum;

collecting at least one prediction noninvasive spectrum of said tissue of said tested subject; and

estimating said biological attribute of said specific subject using said adjusted model; and

displaying said biological attribute.