Prothrombin test apparatus for home use
First Claim
1. An apparatus for determining prothrombin time, suitable for home use, comprising:
- a compartment assembly which includes a reservoir for blood, the reservoir including a blood clotting agent;
means for obtaining blood from a person being tested;
means for moving said blood into the reservoir;
an ultrasound signal device for generating an ultrasound signal and transmitting it through the blood in the reservoir both at a time when the reservoir contains blood which has not yet begun to clot but in a quantity sufficient to sustain two-way transmission of the ultrasound signal and when the blood has substantially clotted, represented by a known increase in the two-way transmission time; and
processing means for determining the prothrombin time of the blood from the time it takes for the two-way transmission time to increase by a known amount.
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Accused Products
Abstract
The apparatus includes a single-use compartment assembly which includes a reservoir for blood and a needle element by which blood is obtained from the user. A vacuum system is actuated which draws blood through the needle element into the blood reservoir. An ultrasound signal is directed through the reservoir. There is no return ultrasound signal until there is sufficient blood in the reservoir. When the blood reaches a given level, it contacts a clotting agent present in the reservoir to begin the clotting process. The ultrasound signals are transmitted and return until clotting has been completed, as determined by a pre-established increase in the two-way propagation time relative to unclotted blood. The prothrombin time is then calculated and compared with an acceptable range.
263 Citations
17 Claims
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1. An apparatus for determining prothrombin time, suitable for home use, comprising:
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a compartment assembly which includes a reservoir for blood, the reservoir including a blood clotting agent;
means for obtaining blood from a person being tested;
means for moving said blood into the reservoir;
an ultrasound signal device for generating an ultrasound signal and transmitting it through the blood in the reservoir both at a time when the reservoir contains blood which has not yet begun to clot but in a quantity sufficient to sustain two-way transmission of the ultrasound signal and when the blood has substantially clotted, represented by a known increase in the two-way transmission time; and
processing means for determining the prothrombin time of the blood from the time it takes for the two-way transmission time to increase by a known amount. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A single use compartment assembly attached to an apparatus for determining prothrombin time, comprising:
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a compartment adapted for removable attachment to said apparatus;
a blood reservoir positioned within the compartment, the reservoir containing a blood clotting agent; and
a needle assembly, communicating with said reservoir for permitting blood obtained from a blood vessel of a person being tested to be moved into said reservoir, wherein the person being tested places a finger on the needle element to produce a puncture contact with a blood vessel and wherein the compartment assembly and the needle assembly are configured as a single unit and are arranged for a single use, and wherein the compartment assembly is readily removable and insertable relative to the apparatus. - View Dependent Claims (17)
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Specification