Method of measuring hematocrit (Hct), sensor used in the method, and measuring device

• US 8,088,271 B2
• Filed: 12/03/2004
• Issued: 01/03/2012
• Est. Priority Date: 12/04/2003
• Status: Active Grant

• Current Assignee: PHC Holdings Corporation
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Fujiwara, Masaki, Shinno, Teppei, Ikeda, Shin
• Primary Examiner(s): Barton, Jeffrey T
• Assistant Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US10/578,988
• Publication Number:
  US 20070062822A1
• Time in Patent Office: 2,587 Days
• Field of Search: 204/409, 204400-40315, 205/777.5, 205/792, 205/775, 205/778
• US Class Current: 205/792
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

The present invention provides a method of electrochemically measuring a hematocrit (Hct) value using a sensor, capable of achieving excellent measurement accuracy and reliability and also provides a sensor used in the method. The method of electrochemically measuring a hematocrit (Hct) value of blood include: providing an electrode system having a working electrode (11) and a counter electrode (12), in which a redox substance is provided on the counter electrode (12) but not on the working electrode (11); supplying blood to the electrode system; applying a voltage to the electrode system in this state to cause an oxidation current or a reduction current to flow between the working electrode (11) and the counter electrode (12); detecting the oxidation current or the reduction current; and determining a Hct value based on a value of the detected current.

Claims

1. A method of electrochemically measuring a hematocrit (Hct) value of blood, comprising:

supplying blood to an electrode system having a working electrode and a counter electrode, a redox substance being provided on the counter electrode but not on the working electrode;

applying a voltage to the electrode system in this state to cause an oxidation current that does not depend on the redox substance or a reduction current that does not depend on the redox substance to flow between the electrodes;

detecting the oxidation current or the reduction current; and

determining a Hct value of the blood based on a value of the detected current.

2. The method according to claim 1, wherein the redox substance comprises a redox substance that is in at least one of an oxidized state and a reduced state.

3. The method according to claim 1, wherein the redox substance is a ferricyanide.

4. The method according to claim 1, wherein the redox substance is potassium ferricyanide.

5. The method according to claim 1, wherein the redox substance is a ferrocyanide.

6. The method according to claim 1, wherein the redox substance is potassium ferrocyanide.

7. The method according to claim 1, wherein the working electrode on which the redox substance is not provided is coated with a polymeric material.

8. The method according to claim 1, wherein the working electrode on which the redox substance is not provided is coated with carboxymethylcellulose.

9. The method according to claim 1, wherein the applied voltage is equal to or higher than a voltage causing electrolysis of water.

10. The method according to claim 1, wherein the applied voltage is 1 to 10 V.

11. The method according to claim 1, wherein the applied voltage is 1 to 6.5 V.

12. The method according to claim 1, wherein

the redox substance is a ferrocyanide, and

a voltage that is negative with respect to a voltage applied to the counter electrode is applied to the working electrode.