Patent ID: 8445287

Claim:
A method for determining a coagulation parameter for a blood or blood component of a living being, comprising: reacting a sample of blood or a blood component containing fibrinogen with a clotting agent that transforms fibrinogen to fibrin by combining said blood sample with said clotting agent; recording, with recording means for making optical measurements, time and optical density values for the sample that correspond with the optical activity of fibrinogen activity during the reaction with the clotting agent, wherein optical density values plotted at their respective corresponding times over the course of the reaction represent a clotting curve; determining the time at which the sample and the clotting agent combined therewith begin to form a change in clotting activity, wherein (T 1 ) represents the time at which the sample and the clotting agent combined therewith begin to form a change in clotting activity, and wherein (c 1 ) represents an optical density value of the sample at the time (T 1 ) where the sample and the clotting agent combined therewith begin to form a change in clotting activity; determining a slope corresponding with a maximum acceleration rate of transformation of fibrinogen to fibrin during the clotting reaction; determining an end of test time (TEOT) corresponding with an optical density value (cEOT) that is indicative of a substantial completion of the reaction of the fibrinogen of the sample and the clotting agent to transform the fibrinogen in the sample to fibrin, wherein said time (TEOT) corresponds with the time at which a line of said slope that represents the rate of maximum acceleration of the clotting activity based on the optical activity of the clotting reaction intersects said optical density value at c=(cEOT); determining a value for an anticoagulant therapy factor (INRs) for the sample, wherein INRs corresponds with a clotting area (A) represented by the time (T 1 ) at which the sample and the clotting agent combined therewith begin to form a change in clotting activity and the time corresponding with the end of test time (TEOT); wherein the clotting area (A) is defined by two sides wherein one side defining said clotting area (A) is represented by the value (T 1 ) and wherein the other side defining said clotting area is represented by the value (TEOT), and wherein the determination of the INRs value is based on the correspondence of a clotting area defined by taking the product of (T 1 ) and (TEOT), and multiplying the said product by a multiplier (MUL), wherein said multiplier (MUL) represents a value based on a sampling rate and a pixel parity value, and wherein said multiplier (MUL) is expressed by the pixel parity value divided by the sampling rate, and wherein said INRs value is expressed by the following relationship: INRs=(T 1 *TEOT)*MUL, where (MUL) is a multiplier that relates the sampling rate at which time and optical activity measurements are recorded with the pixel parity of the x-y-axis of the clotting curve.