Ratiometric immunoassay method and blood testing device

• US 9,778,251 B2
• Filed: 05/01/2015
• Issued: 10/03/2017
• Est. Priority Date: 12/03/2010
• Status: Active Grant

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Inventors: Miller, Cary James
• Primary Examiner(s): BROWN, MELANIE YU
• Application Number:
  US14/702,511
• Publication Number:
  US 20150247842A1
• Time in Patent Office: 886 Days
• 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: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: G01N 2333/4737 C-reactive protein
• CPC Class Codes: G01N 2333/805 Haemoglobins; Myoglobins
• CPC Class Codes: G01N 33/54306 Solid-phase reaction mechanisms
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 33/76 Human chorionic gonadotropin including luteinising hormone, follicle stimulating hormone, thyroid stimulating hormone or their receptors

Abstract

The invention is to devices and methods for rapid determination of analytes in liquid samples. The devices and methods incorporate a sample dilution feature and multiple immunosensors for performing a ratiometric immunoassay on a first analyte and a second analyte, for example, hemoglobin and hemoglobin Alc or albumin and glycosylated albumin. The devices are preferably capable of being used in the point-of-care diagnostic field.

Claims

1. A method of performing an immunoassay in a blood sample, comprising:

introducing a blood sample into a sample entry port of a cartridge and into a sample holding chamber oriented between said sample entry port and a sample extraction unit, wherein a distal portion of said extraction unit defines a metered volume of sample for dilution;

loading said extraction unit with said sample;

expelling a diluent into a diluent conduit oriented between a diluent entry port and a diluent introduction port and having an air introduction port disposed therebetween for introduction of air into the diluent conduit, wherein a volume within the diluent conduit between the air introduction port and the diluent introduction port defines the volume of the diluent;

introducing air into the diluent conduit via the air introduction port to pump the volume of the diluent through the diluent introduction port and over and/or through the sample extraction unit and to wash a portion of said sample from the sample extraction unit to form a diluted sample;

transferring said diluted sample to a sensing region comprising a first sensor and a second sensor, said first sensor comprising an immunosensor for a first analyte and said second sensor comprising an immunosensor for a second analyte;

forming a first sandwich on said first sensor comprising an immobilized first antibody, the first analyte and a first labeled antibody;

forming a second sandwich on said second sensor comprising an immobilized second antibody, the second analyte and a second labeled antibody;

washing said diluted sample from the sensing region;

generating a first signal from the first labeled antibody;

generating a second signal from the second labeled antibody;

detecting the first signal; and

,

detecting the second signal.

2. The method of claim 1, further comprising the step of determining the fractional percentage of the first analyte to the second analyte from the first and second signals.

3. The method of claim 1, wherein the blood sample is amended with an anticoagulant.

4. The method of claim 1, wherein said extraction unit comprises a porous hydrophilic material.

5. The method of claim 1, wherein said extraction unit comprises a cellulose material.

6. The method of claim 1, wherein said extraction unit comprises nitrocellulose.

7. The method of claim 1, wherein said extraction unit comprises cotton fiber.

8. The method of claim 1, wherein said extraction unit comprises paper.

9. The method of claim 1, wherein said extraction unit comprises glass-filled paper.

10. The method of claim 1, wherein said extraction unit comprises a transverse filter material.

11. The method of claim 1, wherein said extraction unit comprises a porous outer coating.

12. The method of claim 1, wherein the first analyte comprises hemoglobin and the second analyte comprises hemoglobin Alc.

13. The method of claim 1, wherein the cartridge comprises a lysing agent capable of dissolving in the sample, the diluent, or the diluted sample.

14. The method of claim 13, wherein said lysing agent comprises sodium deoxycholate.

15. The method of claim 13, wherein said lysing agent comprises saponin.

16. The method of claim 1, wherein the first analyte comprises albumin and the second analyte comprises glycosylated albumin.

17. The method of claim 1, wherein the metered volume of said sample is diluted to an analyte concentration range where the first sensor response is quasi-linear.

18. The method of claim 1, wherein the metered volume of said sample is diluted to an analyte concentration range where the second sensor response is quasi-linear.

19. The method of claim 1, wherein the diluted sample has a dilution ratio of from about 50:

1 to about 50,000;

1 (v/v diluent;

sample).

20. The method of claim 1, wherein the sample extraction unit is configured to become saturated with a portion of the blood sample.

21. The method of claim 1, wherein the step of transferring comprises pumping the diluted sample to the sensing region.

22. The method of claim 1, wherein the cartridge comprise a diluent chamber in fluid communication with the diluent conduit and containing the diluent.