US 5,174,961 AGranted

High sensitivity coagulation detection apparatus

AssigneeHemotec, Inc.

InventorLeland B. Smith

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Abstract

Coagulation related activities are detected in a fluid sample in a plunger sensor cartridge. The cartridge includes a test cell with a reagent chamber and a reaction chamber and a plunger assembly. A reagent drive subassembly forces the contents of the reagent chamber into the reaction chamber. The plunger assembly is raised and released by a plunger lifting subassembly to allow it to descend through the sample of liquid in the bottom of the reaction chamber. A dispenser subassembly automatically meters precise quantities of fluid into the test cells. The plunger lifting subassembly and the reagent drive subassembly are mechanically separate and are controlled separately. Stepper motors are used to provide precise control over the degree, rate and sensitivity of movement of the plunger lifting subassembly, the reagent drive subassembly and the dispensing subassembly.

Claims27

Dependent claims

In an apparatus for conducting an analytical test to detect coagulation related activity of a sample of fluid using a plunger sensing cartridge, the cartridges including at least one vertically extending tube-like test cell having a reagent initially confined in a reagent chamber, the reagent chamber defined in part by a movable plug member movably positioned at a lower end of the test cell, the test cell also including a reaction chamber located above the reagent chamber and extending to an open upper end of the test cell, the reaction chamber containing the sample of fluid, the reaction chamber connected in fluid communication with the reagent chamber by a passageway, the cartridge further including a plunger assembly located in the reaction chamber and retained for generally vertical reciprocative movement within the sample of fluid contained in the reaction chamber, said apparatus comprising plunger lifting means for contacting the plunger assembly and operatively lifting the plunger assembly within the sample of fluid in the reaction chamber and releasing the plunger assembly to allow a fluid resistance property of the sample to control the descent of the plunger assembly, said apparatus further comprising reagent drive means for moving the plug member upward to collapse the reagent chamber and force the reagent through the passageway into the reaction chamber prior to commencement of the test;

and an improvement to said apparatus in combination therewith comprising:
dispensing means for automatically dispensing a predetermined quantity of a sample of the fluid to be tested into each reaction chamber through the open end of each test cell prior to the commencement of the test, the dispensing means dispensing the sample prior to the plunger lifting means contacting the plunger assembly for the lifting and releasing of the plunger assembly.

In an apparatus for conducting analytical tests to detect coagulation related activity of samples of fluids using a plunger sensing cartridge, the cartridge including a plurality of vertically extending tube-like test cells, each test cell having a reagent initially confined in a reagent chamber, the reagent chamber defined in part by a moveable plug member movably positioned at a lower end of the test cell, the test cell also including a reaction chamber located above the reagent chamber and extending to an open upper end of the test cell, the reaction chamber containing a sample of fluid, the reaction chamber connected in fluid communication with the reagent chamber by a passageway, the cartridge further including a plunger assembly located in the reaction chamber of each test cell and retained for generally vertical reciprocative movement within the sample of fluid contained in the reaction chamber, said apparatus comprising reagent drive means and plunger lifting means, the reagent drive means moving the plug member of each test cell upward to collapse the reagent chamber and force the reagent through the passageway into the reaction chamber in each test cell, the plunger lifting means operatively lifting the plunger assembly within the sample of fluid in the reaction chamber of each test cell and releasing the plunger assembly to allow a fluid resistance property of the sample in the reagent chamber to control the descent of each plunger assembly, the descent of the plunger assembly against the resistance of the sample thereby indicating the coagulation related activity of the fluid;

and an improvement in combination therewith comprising:
dispensing means for automatically dispensing a predetermined quantity of a sample of the fluid to be tested into each reaction chamber of each test cell of the cartridge, the dispensing means further comprising:
movement means operatively positioned with respect to the cartridge in the apparatus for lateral movement with respect to the vertical extension of the test cells of the cartridge;
syringe retaining means connected to the movement means and operative for accepting and holding a conventional medical syringe having a tubular body with an open first end into which a syringe plunger is movably fit and a second end from which fluid contained in the body is expelled upon movement of the syringe plunger toward the second end;
and
syringe plunger drive means connected to the movement means and operative for driving the syringe plunger into the syringe body to expel a predetermined amount of the sample of fluid from the second end of the syringe body;
the movement means operatively moving the syringe to a predetermined position relative to each reaction chamber of each of the test cells of the cartridge to deliver the expelled sample of fluid into each reaction chamber.

4 more elements

In an apparatus for conducting analytical tests to detect coagulation related activity of samples of fluids using a lunger sensing cartridge, the cartridge including a plurality of vertically extending tube-like test cells, each test cell having a reagent initially confined in a reagent chamber, the reagent chamber defined in part by a movable plug member movably positioned at a lower end of the test cell, the test cell also including a reaction chamber located above the reagent chamber and extending to an open upper end of the test cell, the reaction chamber containing a sample of fluid, the reaction chamber connected in fluid communication with the reagent chamber by a passageway, the cartridge further including a plunger assembly located in the reaction chamber of each test cell and retained for generally vertical reciprocative movement within the sample of fluid contained in the reaction chamber, each plunger assembly including a plunger shaft extending through the reaction chamber and terminating with at least one flag located exteriorly of and spaced from the open end of the test cell, said apparatus comprising reagent drive means and plunger lifting means, the reagent drive means moving the plug member of each test cell upward to collapse the reagent chamber and force the reagent through the passageway into the reaction chamber in each test cell, the plunger lifting means lifting the plunger assembly within the sample of fluid in the reaction chamber of each test cell and releasing the plunger assembly to allow a fluid resistance property of the sample to control the descent of the plunger assembly, the descent of the plunger assembly against the resistance of the sample thereby indicating the coagulation related activity of the fluid;

and an improvement to said plunger lifting means comprising:
a frame member;
a retaining member retained to the frame member and moveable to a front and a rear position in which to hold the cartridge in place for testing and to allow the insertion and removal of cartridge, respectively;
an arm operative attached to the retaining maimer at a rearward position thereof and expending generally downward from the retaining member;
a pivot shaft pivotably mounted to and carried by the retaining member;
at least one plunger lift wire connected to the pivot shaft carried by the retaining member, the lift wire including a segment extending parallel to the axis of the pivot shaft at a position radially spaced from the axis of the pivot shaft at a forward location of the retaining member;
a lever connected to the pivot shaft and extending radially outward in a generally downward and rearward direction from the pivot shaft;
a plunger lift motor attached to the frame member, the plunger lift motor having an output shaft;
a wheel connected to and rotational about an axis of the output shaft for the plunger lift motor, the wheel rotational axis located in a generally downward and rearward location relative to the retaining member;
a first projection extending from the wheel at an eccentric position relative to the wheel rotational axis and located to contact the arm upon rotation of the wheel through a first predetermined arcuate segment, the contact of the first projection with the arm during rotation of the wheel through the first predetermined segment of rotation moving the arm and the connected retaining member between the rearward and forward positions;
a second projection extending from the wheel at an eccentric position relative to the wheel rotational axis and located to contact the lever upon rotation of the wheel through a second predetermined arcuate segments, the contact of the second projection with the lever during rotation of the wheel through the second predetermined segment of rotation to pivot the pivot shaft and the attached lift wire and move the horizontal segment of the lift wire with alerting and lowering movement.

8 more elements

In an apparatus for conducting analytical tests to detect coagulation related activity of samples of fluids using a plunger sensing cartridge, the cartridge including a plurality of vertically extending tube like test cells, each test cell having a reagent initially confined in a reagent chamber, the reagent chamber defined in part by a moveable plug member movably positioned at a lower end of the test cell, the test cell also including a reaction chamber located above the reagent chamber and extending to an open upper end of the test cell, the reaction chamber containing a sample of fluid, the reaction chamber connected in fluid communication with the reagent chamber by a passageway, the cartridge further including a plunger assembly located in the reaction chamber of each test cell and retained for generally vertical reciprocative movement with the sample of fluid contained in the reaction chamber, said apparatus comprising a receiving block having a receptacle for receiving each one of the plurality of tube like test cells of the cartridge, the bottom of each receptacle being open, reagent drive means including a drive rod extending to project into the open bottom of each receptacle to contact and move the plug member of each test cell to collapse the reagent chamber and force the reagent through the passageway into the reaction chamber in each test cell, plunger lifting means for lifting the plunger assembly within the sample of fluid in the reaction chamber of each test cell and releasing the plunger assembly to allow a fluid resistance property of the sample to control the descent of each plunger assembly, the descent of the plunger assembly against the resistance of the sample thereby indicating the coagulation related activity of the fluid;

and an improvement to said reagent drive means comprising:
a frame member;
a reagent drive motor connected to the frame member and having an output shaft to be rotated by the reagent drive motor;
a first drive wheel attached to the output shaft of the reagent drive motor;
a second drive wheel rotatably mounted at a fixed position relative to the frame member;
a belt rotatably connecting the first and second drive wheels;
a projection extending from the second drive wheel at an eccentric position relative to the rotational axis of the second drive wheel;
at least one vertical guide rod attached to the frame member and the receiving block;
a drive bar slidably mounted on the vertical guide rod to travel in a direction parallel to the extent of the vertical guide rod, each drive rod connecting to the drive bar;
and
an elongated sot formed in the drive bar and operatively positioned to receive therein the projection extending from the second drive wheel;
the engagement of the projection with the slot translating rotation movement of the second drive wheel into linear movement of the drive bar to extend each drive rod into the open ends of the receptacles upon movement of the drive bar toward the receiving block to push the plug members and collapse the reagent chamber.

9 more elements

Dependencies are inferred from the claim text.