Method for non-invasive determination of glucose in body fluids

• US 5,890,489 A
• Filed: 07/30/1996
• Issued: 04/06/1999
• Est. Priority Date: 04/23/1996
• Status: Expired due to Term

• Current Assignee: Dermal Devices Inc.
• Original Assignee: Dermal Therapy (Barbados) Inc.
• Inventors: Elden, Harry Richardson
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): CAMPEN, KELLY SCAGGS
• Application Number:
  US08/688,650
• Time in Patent Office: 980 Days
• Field of Search: 128/898, 435/14, 600/306, 600/307, 600/309, 600/310, 600/316, 600/326, 600/346, 600/347, 600/365, 600/547
• US Class Current: 128/898
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement

Abstract

Method for non-invasively determining glucose level in fluid of subject, typically blood glucose level. A particular device is mounted on the skin of the patient for a fixed period of time. The device is mounted on the skin such that a substrate such as paper or gel or an aqueous glucose solution carried by the device are in contact with the patient'"'"'s skin. Water and/or glucose migrates between the substrate or the aqueous glucose solution of the device. The degree of migration of the substance in question is monitored, for example the amount of glucose remaining in an aqueous solution of the device is measured at the end of the fixed period. This can be done by a conventional or other spectrophotometric method, for example. The glucose level is determined based on the degree of migration of the migrating substance. That is, the degree of migration is correlated with previously determined fluid glucose levels based on directly measured fluid glucose levels. In another approach, impedance alone is measured at the skin surface over a relatively short time period, even less than one second and the impedance is correlated with previously determined glucose levels. It is thus possible, through such a correlation, to routinely non-invasively determine fluid glucose levels.

Claims

1. A method for non-invasively monitoring glucose in a body fluid of subject, the method comprising:

continuously measuring impedance of the skin at a site of the outer skin of the subject; and

quantitatively determining the amount of glucose in the body fluid based upon the measurement.

2. The method of claim 1 wherein the impedance is measured for a period of time between about just more 0 seconds and about 30 seconds.

3. The method of claim 2 wherein the time period is between about 0.5 seconds and about 10 seconds.

4. The method of claim 3 wherein the time period is between about 1 second and about 5 seconds.

5. The method of claim 3 wherein the time period is about 5 seconds.

6. The method of claim 1 wherein the impedance is determined at a site on the forearm or finger tip of the subject.

7. The method of claim 1 wherein the body fluid is blood.

8. The method of claim 1 wherein a plurality of said impedance measurements is taken and the determination is based on an average of said measurements.