CLOT-TIMING SYSTEM AND METHOD

• US 3,635,678 A
• Filed: 06/13/1969
• Issued: 01/18/1972
• Est. Priority Date: 06/13/1969
• Status: Expired due to Term

• Current Assignee: Technicon Instruments Corporation (Bayer AG)
• Original Assignee: John G. Bowen, Lamont J. Seitz
• Inventors: Bowen, John G., Seitz, Lamont J.
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US04/846,992
• Time in Patent Office: 949 Days
• Field of Search: 23/230,23B,253,259 73/54,64.1 356/39 250/218,222 206/84,47A
• US Class Current: 436/69
• CPC Class Codes: G01N 11/10 by moving a body within the material
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/56

Abstract

A system and method is provided which has the general capabilities of measuring the speed of coagulation, congealing or solidification of a fluid sample, and which has particular utility in the measurement of the time required by a sample under test to increase viscosity to a particular level. The system and method to be described is predicated on a viscosity principle, and it includes a member suspended in the fluid sample and which changes position when the sample achieved a predetermined degree of viscosity. The change in position of the aforesaid member is sensed, and the time at which the change occurs, is used in the determination of the time required, for example, for the sample to form a fibrin clot, in a blood or plasma sample or to effect a particular reaction causing solidification or congealing of the sample.

Claims

2. The combination defined in claim 1 in which said sensing means includes a light source positioned to direct light through said fluid to be interrupted by said magnetic member when said magnetic member is in said predetermined position, and photoelectric means positioned to receive light from said light source upon movements of said magnetic member away from sAid predetermined position.

3. The combination defined in claim 2 and which includes a block providing a housing for said magnetic means and for said sensing means, and which includes electric heater means mounted in said block for maintaining said block at a predetermined temperature.

4. The combination defined in claim 3 in which said block has a plurality of incubation wells therein established at said predetermined temperature for storing receptacles of the fluid to be tested and for maintaining said fluids at said predetermined temperature.

5. The combination defined in claim 3 in which said block includes a well adjacent said magnetic means and said sensing means for receiving the aforesaid receptacle means, and said system includes means extending into said well for moving said receptacle means reciprocally past said magnetic means and said sensing means.

6. The combination defined in claim 1 in which said magnetic member is in the form of a steel ball approximating the inner diameter of said receptacle.

7. The combination defined in claim 1 and which includes a timer means for measuring the time required for the viscosity of the fluid sample to exceed said predetermined threshold.

8. The combination defined in claim 7 in which said timer means includes a pulse generator, an impulse counter, and control circuitry for selectively connecting said pulse generator to said impulse counter.

9. The combination defined in claim 8 in which said pulse generator includes a magnetically operated reed switch, magnetic means, and means for cyclically bringing said magnetic means into operative relationship with said reed switch to actuate said switch.

10. The combination defined in claim 9 in which said magnetic means includes a permanent bar magnet, and in which said last-named means includes a turntable supporting said bar magnet adjacent said reed switch and an electric motor for imparting rotational movement to said turntable to bring said bar magnet in and out of operative magnetically coupled relationship with said reed switch.

11. In combination for use in apparatus for sensing changes in viscosity of a fluid blood or blood plasma sample, receptacle means containing a fluid thromboplastin or partial thromboplastin reagent, and a magnetic ball positioned in the fluid in the receptacle, said ball having a diameter approximating the inner diameter of said receptacle.

12. The combination defined in claim 11 in which said receptacle comprises a test tube and stopper means sealing said test tube and retaining the aforesaid reagent therein.

13. The combination defined in claim 11 in which said test tube has a bore diameter of the order of 0.199 inch, and said magnetic member is in the form of a ball having a diameter of the order of 0.187 inch.

14. The combination defined in claim 11 in which said magnetic member is in the form of a steel ball approximating the inner diameter of said receptacle.

15. A method for determining the time of reaction by sensing changes in viscosity of a fluid sample undergoing reaction comprising:

suspending a magnetic member contained within said fluid sample within a steady state magnetic force field, imparting relative movement between the fluid sample and said magnetic force field, and sensing movement of said magnetic member from a predetermined position within said magnetic force field, said movement being controlled so that the magnetic member does not break the surface of the fluid sample.

16. A method for determining the time of clotting of blood and blood plasma comprising:

suspending a magnetic ball contained in a fluid sample of said blood or plasma in admixture with thromboplastin or partial thromboplastin within a steady state magnetic force field, said fluid sample being confined in a transparent tubular container of restricted clearance between the said magnetic ball and the sidewall of the container due to the magnetic ball having a diameter approximating the inner diameter of Said test tube, imparting relative movement between the magnetic force field and the fluid sample to cause the magnetic ball to move up and down in said tubular container, adding a solution containing soluble calcium ions to said fluid sample, and measuring the time interval until said magnetic ball is moved from the original position in the magnetic force field by the formation of a clot in said sample, said movement being controlled so that the magnetic ball does not break the surface of the fluid sample.

17. A method for sensing changes in viscosity of a fluid sample which comprises:

including a magnetic member in the fluid;

creating a magnetic field in the fluid for suspending the magnetic member in a particular position with respect to the magnetic field so long as the viscosity of the fluid is below a predetermined threshold;

imparting relative vertical reciprocating movement between said fluid and said magnetic field; and

sensing any movement of said magnetic member away from said particular position with respect to said magnetic field, said movement being controlled so that the magnetic member does not break the surface of the fluid sample.

18. The method defined in claim 17 and which includes:

directing a light beam through the fluid to be normally interrupted by said magnetic member; and

receiving the light beam upon movement of said magnetic member away from said particular position.

19. The method defined in claim 18, and which includes converting the received light beam into electrical energy.

20. The method defined in claim 17 and which includes imparting reciprocal movement to said fluid in a vertical direction.

21. The method defined in claim 17 and which includes timing the interval required for the magnetic member to move away from said particular position.

22. A method for sensing changes in viscosity of a fluid sample which includes providing a magnetic member in the fluid;

creating a magnetic field in the fluid for holding the magnetic member in a particular position with respect to the magnetic field so long as the viscosity of the fluid is below a predetermined threshold;

imparting reciprocal movement to said fluid in a vertical direction with respect to said magnetic field;

directing a light beam through the fluid to be normally interrupted by said magnetic member;

receiving the light beam upon movement of said magnetic member away from said particular position;

converting the received light beam into electrical energy; and

timing the interval required for the magnetic member to move away from said particular position, said movement being controlled so that the magnetic member does not break the surface of the fluid sample.

23. The method defined in claim 17 and which comprises mixing thromboplastin or partial thromboplastin and plasma in the fluid sample.

24. The method defined in claim 17 and which comprises mixing thromboplastin, or partial thromboplastin, plasma and a source of soluble calcium ions in the fluid sample.

25. The method defined in claim 24 in which the thromboplastin or partial thromboplastin, plasma and source of soluble calcium ions are mixed in the sample in substantially equal proportions.

26. The method defined in claim 25 in which the thromboplastin or partial thromboplastin, plasma and source of soluble calcium ions are brought to a test temperature of the order of 37* C.

27. The method defined in claim 25 in which approximately one-tenth of a milliliter each of thromboplastin or partial thromboplastin, plasma and calcium chloride are mixed in substantially equal proportions in the sample.

28. Apparatus for sensing changes in viscosity of a fluid sample including:

receptacle means for the fluid;

a magnetic member in the fluid in the receptacle means;

magnetic means for creating a magnetic field in the receptacle to hold said magnetic member in a predetermined position with respect to said magnetic field so long as the viscosity of said fluid is below a predetermined Threshold and in the presence of relative movements between said fluid and said magnetic field;

means for sensing movements of said magnetic member away from said predetermined position in the presence of the aforesaid relative movements;

a block providing a housing for said magnetic means and for said sensing means and including a well adjacent said magnetic means and said sensing means for receiving said receptacle means;

a piston extending vertically into said well from the lower end thereof and reciprocally movable within said well for moving said receptacle means reciprocally past said magnetic means and said sensing means; and

a drive mechanism coupled to said piston for imparting vertical reciprocal movement to said piston within said well.

29. The apparatus defined in claim 28 in which said sensing means includes a light source positioned to direct light through said fluid to be interrupted by said magnetic member when said magnetic member is in said predetermined position;

and photoelectric means positioned to receive light from said light source upon movements of said magnetic member away from said predetermined position.

30. The apparatus defined in claim 28 and which includes a timer mechanism for measuring the time required for the viscosity in the fluid sample to exceed said predetermined threshold.

31. The apparatus defined in claim 30 and in which the timer mechanism includes a pulse generator having a magnetically operated reed switch;

magnetic means;

a turntable supporting said magnetic means and positioned relative to said reed switch for cyclically bringing said magnetic means into operative relationship with said reed switch; and

an electric motor for imparting rotational movement to said turntable.

32. Apparatus for sensing changes in viscosity of a congealable fluid sample including:

a receptacle means for the fluid;

a magnetic member suspended in the fluid in the receptacle;

magnetic means for creating a magnetic field in the receptacle for holding said magnetic member in a predetermined position with respect to said magnetic field so long as the viscosity of said fluid is below a predetermined threshold and in the presence of relative movements between said fluid and said magnetic field;

means coupled to at least one of the aforesaid means for imparting relative vertical reciprocating movement between said receptacle and said magnetic field; and

photoelectric means for sensing movements of aid magnetic member away from said predetermined position in the presence of the aforesaid relative vertical movement.

33. The combination defined in claim 32 and which includes a block providing a housing for said magnetic means and for said photoelectric sensing means and a well adjacent said sensing means for receiving the aforesaid receptacle means, and which includes electric heater means mounted in said block for maintaining said block at a predetermined temperature.

34. The combination defined in claim 33 in which said block has a plurality of incubation wells therein established at said predetermined temperature for storing receptacles of the fluid to be tested and for maintaining said fluids at said predetermined temperature.

35. The combination defined in claim 32 in which said magnetic member is in the form of a steel ball.

36. The combination defined in claim 32 and which includes a timer means for measuring the time required for the viscosity of the fluid sample to exceed said predetermined threshold.

37. The combination defined in claim 36 in which said timer means includes a pulse generator, an impulse counter, and control circuitry for selectively connecting said pulse generator to said impulse counter.

38. The combination defined in claim 37 in which said pulse generator includes a magnetically operated reed switch, magnetic means, and means for cyclically bringing said magnetic means into operative relationship with said reed switch to actuate said switch.

39. The combination defined in claim 38 in which said magneTic means includes a permanent bar magnet, and in which said last-named means includes a turntable supporting said bar magnet adjacent said reed switch and an electric motor for imparting rotational movement to said turntable to bring said bar magnet in and out of operative magnetically coupled relationship with said reed switch.

40. A method for determining the time of reaction by sensing changes in viscosity of a congealable fluid sample undergoing reaction comprising:

suspending a magnetic member contained within said fluid sample within a steady state magnetic force field, imparting relative vertical reciprocating movement between the fluid sample and said magnetic force field, and photoelectrically sensing movement of said magnetic member from a predetermined position within said magnetic force field.