Method for providing custom calibration for near infrared instruments for measurement of blood glucose

• US 5,068,536 A
• Filed: 04/09/1991
• Issued: 11/26/1991
• Est. Priority Date: 01/19/1989
• Status: Expired due to Term

• Current Assignee: Futrex, Inc.
• Original Assignee: Futrex, Inc.
• Inventors: Rosenthal, Robert D.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US07/682,249
• Time in Patent Office: 231 Days
• Field of Search: 250/339, 250/341, 250/343, 356/39, 128/633
• US Class Current: 250/341.5
• CPC Class Codes: A61B 5/0008 Temperature signals
• 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 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427

Abstract

A method is disclosed for easily and reliably custom calibrating near-infrared quantitative analysis instruments including obtaining a plurality of blood samples and blood glucose level measurements thereof at a predetermined time interval. These values are entered into the analysis instrument. Near-infrared optical measurements of the individual are simultaneously taken using the analysis instrument at another predetermined time interval. Calibration regression analysis is performed on the data to custom calibrate the analysis instrument which involves linearly interpolating the blood sample glucose measurements with the near-infrared optical recordings.

Claims

1. A method for calibrating a near-infrared analysis instrument for the measurement of blood glucose, said method comprising:

(a) obtaining a plurality of blood samples from an individual each at a first predetermined time interval during a predetermined period of time and obtaining a blood glucose level measurement for each said blood sample;

(b) obtaining near-infrared optical absorption measurements through a body part of said individual at a second predetermined time interval and during said predetermined period of time, and recording said measurements; and

(c) performing calibration regression analysis utilizing means for linearly interpolating said blood sample glucose level measurements with said near-infrared optical absorption measurements to calibrate said near-infrared analysis instrument for said individual.

2. The method as set forth in claim 1 wherein said first predetermined time interval is between approximately 10 and approximately 20 minutes.

3. The method as set forth in claim 1 wherein said second predetermined time interval is between approximately one and approximately three minutes.

4. The method as set forth in claim 1 wherein said predetermined period of time is between approximately 45 and approximately 90 minutes.

5. The method as set forth in claim 4 wherein said predetermined period of time is approximately 60 minutes.

6. The method as set forth in claim 2 wherein said first predetermined time interval is approximately 15 minutes.

7. The method as set forth in claim 1 wherein said first predetermined time interval comprises time periods at least one of which has an unequal duration relative to at least one other of said time periods.

8. The method as set forth in claim 1 wherein approximately 40 to approximately 90 optical absorption measurements are made.

9. The method as set forth in claim 8 where a regression analysis algorithm used in said linear interpolation utilizes approximately three or four regression terms.

10. The method as set forth in claim 1 further comprising the following steps:

(a) placing said body part in a plurality of environments, each of said environments having a temperature different from each other of said environments, and producing a temperature change in said body part from a normal temperature of said body part; and

(b) obtaining at least one of said near-infrared optical absorption measurements through said body part after said temperature change has been produced in said body part.

11. A method for calibrating a near-infrared analysis instrument for the measurement of an unknown value of an known characteristic of blood, said method comprising:

(a) obtaining a plurality of blood samples from an individual each at a first predetermined time interval during a predetermined period of time and obtaining a value of said known characteristic for each blood sample;

(b) obtaining near-infrared optical absorption measurements through a body part of said individual at a second predetermined time interval and during said predetermined period of time, and recording said measurements; and

(c) performing calibration regression analysis utilizing means for linearly interpolating each said value of said known characteristic for each said blood sample with said near-infrared optical absorption measurements to calibrate said near-infrared analysis instrument for said individual.