Reaction cassette for preforming sequential analytical assays by noncentrifugal and noncapillary manipulations

• US 5,162,237 A
• Filed: 10/08/1991
• Issued: 11/10/1992
• Est. Priority Date: 04/11/1988
• Status: Expired due to Term

• Current Assignee: Siemens Healthcare Diagnostics Incorporated (Siemens AG)
• Original Assignee: Miles, Inc. (Bayer AG)
• Inventors: Messenger, Lowry J., Nelson, Christine D., Wogoman, Frank W., Yip, Kin-Fai
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): REDDING, DAVID A
• Application Number:
  US07/774,362
• Time in Patent Office: 399 Days
• Field of Search: 422/55, 422/58, 422/61, 422/72, 422/102, 435/299, 435/312, 436/45, 436/17, 436/67, 436/165, 436/501, 436/518, 436/522, 436/523, 436/526, 436/528, 436/533, 436/536, 436/807, 436/808
• US Class Current: 436/523
• CPC Class Codes: B01L 3/502 with fluid transport, e.g. in multi-compartment structures centrifugal-type cuvettes G01N21/07; analysis by separation into components G01N30/00; automatic analysers G01N35/00
• CPC Class Codes: G01N 21/07 Centrifugal type cuvettes G01N21/09 takes precedence
• CPC Class Codes: G01N 33/5302 Apparatus specially adapted for immunological test procedures
• CPC Class Codes: G01N 33/5304 Reaction vessels, e.g. agglutination plates for solid-phase systems G01N33/543
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/723 Glycosylated haemoglobin
• CPC Class Codes: G01N 33/726 Devices
• CPC Class Codes: Y10S 436/808 Automated or kit

Abstract

Analytical reaction cassette and method for performing sequential analytical assay procedures to determine the amount of an analyte in a liquid test mixture. The reaction cassette can be in the form of a substantially square container having a substantially horizontal axis of rotation and incorporated with one or more analytical reagents such that they are contacted with a liquid test mixture in a desired ordered sequence to perform a particular assay procedure. Corners provided by the substantially square configuration of the reaction cassette disrupt the flow of liquids disposed in the reaction cassette upon contact therewith to thereby agitate and mix such liquids. A liquid disposed in the reaction cassette is capable of being manipulated and mixed therein by rotating the reaction cassette about the horizontal axis at sufficiently low velocities wherein the transport of such liquid is noncentrifugal and due substantially only to gravitational force. The reaction cassette is particularly useful for performing immunoturbidimetric assays, e.g., for the determination of glycated hemoglobin.

Claims

1. A method for performing analytical reactions to determine an analyte in a liquid test sample, said method comprising the steps of:

(a) providing a reaction cassette having a substantially horizontal axis of rotation, said reaction cassette comprising

(1) inlet means for introducing a liquid test sample into said reaction cassette, and

(2) a reaction channel is open liquid communication with said inlet means and comprising

(i) a reagent zone incorporated with an analytical reagent which interacts with said analyte to produce a detectable response as a function of the analyte, and

(ii) means for disrupting the flow of a liquid by gravity along said reaction channel sufficient to agitate said liquid upon contact therewith;

(b) introducing the liquid test sample into said reaction channel of said reaction cassette through said inlet means and forming a liquid reaction mixture in said reaction channel;

(c) rotating said reaction cassette about said horizontal axis to transport said liquid mixture by gravity along said reaction channel into contact with said analytical reagent in said reagent zone and into contact with said flow disrupting means;

(d) oscillating said reaction cassette about said horizontal axis to agitate said liquid mixture in contact with said flow disrupting means sufficiently to thoroughly mix the test sample and analytical reagent in said mixture; and

(e) measuring said detectable response in said liquid mixture.

2. The method of claim 1 wherein said flow disrupting means is situated along said reaction channel a sufficient distance from said reagent zone that said liquid mixture can be in contact with said reagent zone without simultaneously being in contact with said flow disrupting means.

3. The method of claim 1 wherein said flow disrupting means and said reagent zone are situated sufficiently proximate to each other that said liquid mixture can be in contact with said flow disrupting means and said reagent zone simultaneously.

4. The method of claim 1 wherein said flow disrupting means comprises an obstruction or a point of convergence in said reaction channel configured such that the gravity flow of a liquid is redirected upon contact of said liquid therewith.

5. The method of claim 1 wherein said flow disrupting means is a corner in an outer perimeter wall portion of said reaction channel which forms an angle of between about 75 degrees and about 105 degrees.

6. The method of claim 5 wherein said corner in said outer perimeter wall portion of said reaction channel forms and angle of about 90 degrees.

7. The method of claim 1 wherein the speed of rotation of said reaction cassette about said horizontal axis used to transport said liquid mixture along said reaction channel and into contact with said reagent and flow disrupting means is sufficiently slow to be essentially noncentrifugal and due substantially only to gravitational force.

8. The method of claim 7 wherein said speed of rotation is between about 1 r.p.m. and about 60 r.p.m.

9. The method of claim 1 wherein the maximum speed of rotation of said reaction cassette during its oscillation to agitate the liquid mixture in contact with said flow disrupting means is between about 15 r.p.m. and about 40 r.p.m.

10. The method of claim 1 wherein said reagent zone is incorporated with a dried form of said analytical reagent.

11. The method of claim 1 wherein said reaction cassette also comprises means for introducing a liquid analytical reagent into said reaction channel.

12. The method of claim 1 wherein said reaction cassette also comprises means for introducing a liquid test sample into said reaction channel through said inlet means.

13. The method of claim 1 wherein said reaction channel further comprises a viewing zone in open liquid flow communication with said reaction zone.

14. The method of claim 13 comprising the step of rotating said reaction cassette about said horizontal axis whereby said liquid mixture is transported by gravity along said reaction channel into said reaction mixture viewing zone.

15. The method of claim 13 wherein a second outer perimeter wall portion of said reaction channel is configured as a corner forming an angle of between about 75 degrees and about 105 degrees, and wherein said corner serves as said reaction mixture viewing zone.

16. The method of claim 1 wherein said reaction channel comprises a plurality of reagent zones incorporated with a plurality of analytical reagents, and wherein rotation of the reaction cassette about its horizontal axis is used to bring the liquid mixture in the reaction channel into contact with each such reagent zones by gravity flow.

17. The method of claim 16 wherein after being brought into contact with a reagent zone, the liquid mixture is agitated in contact with flow disrupting means by oscillation of the reaction cassette about its horizontal axis.

18. An immunoturbidometric method of determining the relative amount of glycated hemoglobin in a whole blood test sample, said method comprising the steps of:

(a) providing a capillary holder that comprises a capillary sampling tube,

(b) drawing said whole blood test sample into the capillary sampling tube in said capillary holder,

(c) providing a reaction cassette having a substantially horizontal axis of rotation, said reaction cassette comprising

(1) a reaction channel situated in the plane of rotation about said horizontal axis and comprising

(i) an outer perimeter wall having first and second corners which form angles in said perimeter wall of between about 75 degrees and about 105 degrees,

(ii) a first reagent zone proximal to said first corner and incorporated with an oxidant capable of converting hemoglobin into its met-hemoglobin form,

(iii) a second reagent zone incorporated with an antibody-particle reagent, and

(iv) a third reagent zone incorporated with an agglutinator reagent;

(2) liquid delivery means for introducing an aqueous solution of hemoglobin denaturant into the reaction channel, and

(3) an inlet port engageable with the capillary holder to position the capillary sampling tube proximate to said first corner of the reaction channel,

(d) engaging said capillary holder in said inlet port of the reaction vessel,

(e) activating said liquid delivery means to release the denaturant solution into the reaction channel of the reaction vessel,

(f) rotating the reaction cassette about its horizontal axis to transport by gravity the denaturant solution along the reaction channel to said first corner of the reaction channel and into contact with the capillary sampling tube and said oxidant in said first reagent zone,

(g) oxcillating the reaction cassette about its horizontal axis to agitate the denaturant solution in said first corner in contact with said capillary sampling tube and the oxidant-incorporated first reagent zone sufficiently to extract the blood sample from the capillary tube and to form a reaction mixture with the denaturant and oxidant,

(h) measuring the absorbance of met-hemoglobin formed in the resulting liquid mixture,

(i) rotating the reaction cassette about its horizontal axis to transport by gravity the liquid reaction mixture along the reaction channel into contact with said second and third reagent zones and said second corner,

(j) oscillating the reaction cassette about its horizontal axis to agitate the liquid reaction mixture in said second corner in contact with the second and third reagent zones sufficiently to thoroughly mix said liquid mixture and the antibody-particle and agglutinator reagents,

(k) measuring the absorbance of the resulting liquid mixture and relating the ratio of the absorbance measured in step (h) to such final absorbance measurement as a function of the relative amount of glycatedhemoglobin in the blood sample tested.

19. The method of claim 18 wherein said first or second corner in the reaction channel provides a viewing zone for measuring the absorbance of liquid mixtures in the reaction channel, and wherein the liquid mixtures are transported by gravity to such corner by rotation of the reaction vessel about its horizontal axis.

20. The method of claim 18 wherein said oxidant comprises a ferricyanide salt.

21. The method of claim 18 wherein said liquid denaturant comprises a thiocyanate salt.

22. The method of claim 18 wherein said antibody particle reagent comprises an antibody, or fragment thereof, to the glycated N-terminal peptide sequence in the beta-subunit of hemoglobin, which antibody or fragment is immobilized to a water suspendable particle.

23. The method of claim 22 wherein said water suspendable particle is a latex particle.

24. The method of claim 18 wherein said agglutinator reagent comprises a plurality of epitopic binding sites for said antibody reagent.

25. The method of claim 24 wherein said epitopic sites are glycated peptide residues corresponding to the glycated N-terminal peptide sequence of hemoglobin.

26. The method of claim 18 wherein said liquid delivery means is centrally located in said reaction cassette.

27. The method of claim 18 wherein said liquid delivery means is in the form of a syringe.

28. The method of claim 18 wherein said liquid delivery means is in the form of a reservoir body closed by a removable, fluid tight seal.

29. The method of claim 18 wherein said corners each form an angle of about 90 degrees.

30. The method of claim 18 wherein the speed of rotation of said reaction cassette about said horizontal axis used in steps (f) and (i) to transport liquid along the reaction channel is sufficiently slow to be essentially noncentrifugal and due substantially only to gravitational force.

31. The method of claim 30 wherein said speed of rotation is between about 1 r.p.m. and about 60 r.p.m.

32. The method of claim 18 wherein the maximum speed of rotation of said reaction vessel during its oscillation to agitate the reaction liquid in performing steps (g) and (j) is between about 15 r.p.m. and about 40 r.p.m.

33. An analytical reaction cassette for performing analytical reactions to determine an analyte in a liquid test sample, said reaction cassette having a substantially horizontal axis of rotation and comprising:

(1) inlet means for introducing a liquid test sample into said reaction cassette, and

(2) a reaction channel in open liquid communication with said inlet means and comprising

(i) a reagent zone incorporated with an analytical reagent which interacts with said analyte to produce a detectable response as a function of the analyte, and

(ii) means for disrupting the flow of a liquid by gravity along said reaction channel sufficient to agitate

said liquid upon contact therewith, whereby a liquid disposed in said reaction channel is transported by gravity along said reaction channel by rotating said reaction vessel about said horizontal axis and thereby brought into contact with said reagent zone and said flow disrupting means.

34. The reaction cassette of claim 33 wherein said flow disrupting means is situated along said reaction channel a sufficient distance from said reagent zone that a liquid can be in contact with said reaction zone without simultaneously being in contact with said flow disrupting means.

35. The reaction cassette of claim 33 wherein said flow disrupting means and said reagent zone are situated sufficiently proximate to each other that a liquid can be in contact with said flow disrupting means and said reagent zone simultaneously.

36. The reaction cassette of claim 33 wherein said flow disrupting means comprises an obstruction or a point of convergence in said reaction channel configured such that the gravity flow of a liquid is redirected upon contact of said liquid therewith.

37. The reaction cassette of claim 33 wherein said flow disrupting means is a corner in an outer perimeter wall portion of said reaction channel which forms an angle of between about 75 degrees and about 105 degrees.

38. The reaction cassette claim 37 wherein said corner in said outer perimeter wall portion of said reaction channel forms an angle of about 90 degrees.

39. The reaction cassette of claim 33 wherein said reagent zone is incorporated with a dried form of said analytical reagent.

40. The reaction cassette of claim 33 also comprising means for introducing a liquid analytical reagent into said reaction channel.

41. The reaction cassette of claim 33 also comprising means for introducing a liquid test sample into said reaction channel through said inlet means.

42. The reaction cassette of claim 33 wherein said reaction channel further comprises a reaction mixture viewing zone in open liquid flow communication with said reaction zone.

43. The reaction cassette of claim 42 wherein a second outer perimeter wall portion of said reaction channel is configured as a corner forming an angle of between about 75 degrees and about 105 degrees, and wherein said corner serves as said reaction mixture viewing zone.

44. The reaction cassette of claim 33 wherein said reaction channel comprises a plurality of reagent zones incorporated with a plurality of analytical reagents.

45. An immunoturbidimetric reaction cassette kit for determining the relative amount of glycated hemoglobin in a whole blood test sample, said kit comprising:

(A) a capillary holder that comprises a capillary sampling tube, and

(B) a reaction cassette body having a substantially horizontal axis of rotation and comprising

(1) a reaction channel situated in the plane of rotation about said horizontal axis and comprising

(i) an outer perimeter wall having first and second corners which form angles in said perimeter wall of between about 75 degrees and about 105 degrees,

(ii) a first reagent zone proximal to said first corner and incorporated with an oxidant capable of converting hemoglobin into its met-hemoglobin form,

(iii) a second reagent zone incorporated with an antibody-particle reagent, and

(iv) a third reagent zone incorporated with an agglutinator reagent,

whereby a liquid disposed in the reaction channel is transported by gravity along said reaction channel and into contact with said corners and said reagent zones by rotation of the reaction cassette about its horizontal axis,

(2) liquid delivery means for introducing an aqueous solution of hemoglobin denaturant into the reaction channel, and

(3) an inlet port engageable with the capillary holder to position the capillary sampling tube proximate to said first corner of the reaction channel.

46. The reaction kit of claim 45 wherein said liquid delivery means is centrally located in said reaction cassette.

47. The reaction kit of claim 45 wherein said liquid delivery means is in the form of a syringe.

48. The reaction kit of claim 45 wherein said liquid delivery means is in the form of a reservoir body closed by a removable, fluid tight seal.

49. The reaction kit of claim 45 wherein one of said corners serves as a reaction viewing zone from which a detectable response can be detected and measured.

50. The reaction kit of claim 45 wherein said oxidant, said antibody particle reagent, and said agglutinator reagent are incorporated as substantially dry, dissolvable forms thereof.

51. The reaction kit of claim 45 wherein said oxidant comprises a ferricyanide salt.

52. The reaction kit of claim 45 wherein said liquid denaturant comprises a thiocyanate salt.

53. The reaction kit of claim 45 wherein said antibody particle reagent comprises an antibody, or fragment thereof, to the glycated N-terminal peptide sequence in the beta-subunit of denatured hemoglobin, which antibody or fragment is immobilized to a suspendable particle.

54. The reaction kit of claim 53 wherein said suspendable particle is a water suspendable latex particle.

55. The reaction kit of claim 45 wherein said agglutinator reagent comprises a plurality of epitopic binding sites for said antibody reagent.

56. The reaction kit of claim 55 wherein said agglutinator reagent comprises glycated peptide residues of glycated hemoglobin.

57. The reaction kit of claim 45 wherein said corners each form an angle of 90 degrees.