Electrochemical coagulation assay and device

• US 6,620,310 B1
• Filed: 12/13/2000
• Issued: 09/16/2003
• Est. Priority Date: 12/13/2000
• Status: Expired due to Term

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Ohara, Timothy J., Teodorczyk, Maria, Shartle, Robert Justice
• Primary Examiner(s): Tung, T.
• Assistant Examiner(s): NOGUEROLA, ALEXANDER STEPHAN
• Application Number:
  US09/736,788
• Time in Patent Office: 1,007 Days
• Field of Search: 204/400, 204/403.01, 205/775, 205/792, 422/73, 436/69
• US Class Current: 205/792
• CPC Class Codes: A61B 10/0045 Devices for taking samples of body liquids devices for taking blood samples A61B5/15
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: B01L 2300/0672 Integrated piercing tool
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: G01N 11/00 Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
• CPC Class Codes: G01N 27/307 Disposable laminated or multilayered electrodes G01N27/3272 takes precedence
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/56
• CPC Class Codes: G01N 33/491 by separating the blood components G01N15/05 takes precedence
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

Methods and devices for electrochemically detecting a change in the viscosity of a fluid are provided. In the subject methods, a fluid sample is introduced into an electrochemical cell having oppositely spaced apart working and reference electrodes. An electric potential is applied to the cell to first achieve a steady state cell current. A decrease in the steady state cell current is then detected and related to a change in viscosity of the sample. In many embodiments, the sample is blood and the change in viscosity is related to the onset of coagulation in the blood sample, and often the PT of the blood sample. Also provided are test strips, kits thereof and meters for use in practicing the subject methods.

Claims

1. A method for detecting a change in the viscosity of a fluid sample, said method comprising:

(a) introducing a sample into an electrochemical cell comprising a redox couple and oppositely spaced apart working and reference electrodes;

(b) applying an electric potential to said reaction cell to produce a peak in current, followed by a steady state current between said oppositely spaced apart electrodes;

(c) detecting a change from said steady state current; and

(d) relating said change in steady state current to a change in viscosity of said fluid sample.

2. The method according to claim 1, wherein said change from steady state current is a decrease.

3. The method according to claim 1, wherein said change in viscosity is an increase.

4. The method according to claim 1, wherein said fluid sample is a physiological sample.

5. The method according to claim 4, wherein said physiological sample is blood.

6. The method according to claim 5, wherein said method further comprises relating said change in viscosity to the prothrombin time (PT) of said blood.

7. A method for detecting the onset of coagulation of a blood sample, said method comprising:

(a) introducing said blood sample into an electrochemical cell comprising;

(i) oppositely spaced apart working and reference electrodes; and

(ii) a reagent mixture comprising a redox couple;

(b) applying an electric potential to said reaction cell to produce a peak in current, followed by a steady state current between said oppositely spaced apart electrodes;

(c) detecting a change from said steady state current; and

(d) relating said change in steady state current to the onset of coagulation in said blood sample.

8. The method according to claim 7, wherein said change is a decrease.

9. The method according to claim 7, wherein said reagent comprises a coagulation catalyzing agent.

10. The method according to claim 9, wherein said coagulation catalyzing agent comprises thromboplastin.

11. The method according to claim 9, wherein said method further comprises relating said onset of coagulation to the prothrombin time of said blood sample.