Blood coagulation test cartridge, system, and method
First Claim
1. A system for performing a test on a blood sample determining a coagulation time comprising:
- a test cartridge comprising a blood receptacle that is open to the atmosphere into which a blood sample is to be deposited, a vacuum port that is open to atmosphere, and a spiral capillary within the test cartridge having a capillary length and cross-section area, a first capillary end of the spiral capillary open to the blood receptacle and a second capillary end of the spiral capillary open to the vacuum port, whereby the spiral capillary is closed to atmosphere; and
a vacuum applicator having a vacuum applicator port adapted to be fitted to the vacuum port to close the vacuum port from atmosphere and further comprising;
a vacuum applicator housing enclosing a vacuum chamber and extending between the vacuum applicator port and a vacuum cylinder;
a piston fitted within the vacuum cylinder;
a drive motor coupled to the piston adapted to be powered upon deposition of the blood sample in the blood receptacle to move the piston at a predetermined fixed rate within the vacuum cylinder that creates a vacuum in the spiral capillary sufficient to aspirate the blood in the receptacle along the spiral capillary toward the vacuum port until a blood clot is formed that blocks further blood aspiration;
a pressure sensor coupled to the vacuum chamber that is operable to measure the vacuum within the vacuum chamber and develop an air pressure signal during movement of the piston;
a pressure change detection circuit for comparing successive pressure signals to detect a change in pressure occurring when a blood clot blocks aspiration of blood through the spiral capillary and generate a clot detection signal; and
a timer for timing the elapsed time from the commencement of the vacuum and generation of a clot detection signal, thereby determining a coagulation time.
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Accused Products
Abstract
A system and method for determining a coagulation time, e.g., thrombin time, PT, aPTT, and ACT, of a blood sample deposited in a test cartridge is disclosed. The test cartridge includes a blood receptacle that is open to the atmosphere into which a blood sample is to be deposited, a vacuum port that is open to atmosphere, and a spiral capillary within the test cartridge having a capillary length and cross-section area, a first capillary end of the spiral capillary open to the blood receptacle and a second capillary end of the spiral capillary open to the vacuum port, whereby the spiral capillary is closed to atmosphere. When a blood sample is deposited in the blood receptacle, a vacuum is drawn through the vacuum port and the blood is drawn through the spiral capillary until coagulation occurs. A pressure change is detected, and the coagulation time is measured.
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Citations
62 Claims
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1. A system for performing a test on a blood sample determining a coagulation time comprising:
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a test cartridge comprising a blood receptacle that is open to the atmosphere into which a blood sample is to be deposited, a vacuum port that is open to atmosphere, and a spiral capillary within the test cartridge having a capillary length and cross-section area, a first capillary end of the spiral capillary open to the blood receptacle and a second capillary end of the spiral capillary open to the vacuum port, whereby the spiral capillary is closed to atmosphere; and a vacuum applicator having a vacuum applicator port adapted to be fitted to the vacuum port to close the vacuum port from atmosphere and further comprising; a vacuum applicator housing enclosing a vacuum chamber and extending between the vacuum applicator port and a vacuum cylinder; a piston fitted within the vacuum cylinder; a drive motor coupled to the piston adapted to be powered upon deposition of the blood sample in the blood receptacle to move the piston at a predetermined fixed rate within the vacuum cylinder that creates a vacuum in the spiral capillary sufficient to aspirate the blood in the receptacle along the spiral capillary toward the vacuum port until a blood clot is formed that blocks further blood aspiration; a pressure sensor coupled to the vacuum chamber that is operable to measure the vacuum within the vacuum chamber and develop an air pressure signal during movement of the piston; a pressure change detection circuit for comparing successive pressure signals to detect a change in pressure occurring when a blood clot blocks aspiration of blood through the spiral capillary and generate a clot detection signal; and a timer for timing the elapsed time from the commencement of the vacuum and generation of a clot detection signal, thereby determining a coagulation time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of performing a test on a blood sample determining a coagulation time comprising:
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providing a test cartridge comprising a blood receptacle that is open to the atmosphere into which a blood sample is to be deposited, a vacuum port that is open to atmosphere, and a spiral capillary within the test cartridge having a capillary length and cross-section area, a first capillary end of the spiral capillary open to the blood receptacle and a second capillary end of the spiral capillary open to the vacuum port, whereby the spiral capillary is closed to atmosphere; depositing a blood sample in the blood receptacle; drawing a vacuum through the vacuum port that creates a vacuum in the spiral capillary sufficient to aspirate the blood in the receptacle along the spiral capillary toward the vacuum port until a blood clot is formed that blocks further blood aspiration; measuring the vacuum drawn within the spiral capillary as blood is aspirated along the spiral capillary; detecting a change in the measured vacuum upon formation of a blood clot that blocks further blood aspiration; and timing the elapsed time between the commencement of the vacuum and detection of the change, thereby determining a coagulation time. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A system for of performing a test on a blood sample determining a coagulation time comprising:
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a test cartridge comprising a blood receptacle that is open to the atmosphere into which a blood sample is to be deposited, a vacuum port that is open to atmosphere, and a spiral capillary within the test cartridge having a capillary length and cross-section area, a first capillary end of the spiral capillary open to the blood receptacle and a second capillary end of the spiral capillary open to the vacuum port, whereby the spiral capillary is closed to atmosphere; means operable after deposition of a blood sample in the blood receptacle for drawing a vacuum through the vacuum port that creates a vacuum in the spiral capillary sufficient to aspirate the blood in the receptacle along the spiral capillary toward the vacuum port until a blood clot is formed that blocks further blood aspiration; means for measuring the vacuum drawn within the spiral capillary as blood is aspirated along the spiral capillary; means for detecting a change in the measured vacuum upon formation of a blood clot that blocks further blood aspiration; and means for timing the elapsed time between the commencement of the vacuum and detection of the change, thereby determining a coagulation time. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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Specification