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US 10,613,077 B2Granted
Clot detection methods for clotting time testing
AssigneeMedtronic Vascular, Inc.
InventorsCharlene Yuan, Lawrence Erickson, Trevor Huang
Life of this patent
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Abstract
Aspects of the disclosure relate to clotting time tests detect clotting time based on the viscosity changes of a fluid sample, using a disk dropped within a test chamber containing the fluid sample from a disk maximal position to a disk minimal position, which is a point at which the disk settles within the fluid sample. Changes in the disk minimal position as multiple test cycles are conducted are used in assessing formation of a clot within the fluid sample. Methods of assessing such changes in the disk minimal position are disclosed.
Claims20
A method of detecting the formation of a clot in a fluid sample during a coagulation test phase including one or more test periods, the method comprising:
- a. providing a test chamber having a top and a bottom and further providing a disk positioned within the test chamber;
- b. filling the test chamber with the fluid sample;
- c. conducting a plurality of test cycles, each test cycle including:
- i. positioning the disk at a disk maximum position within the test chamber;
- wherein the disk maximum position is the highest point at which the disk is positioned during the respective test cycle;
- ii. dropping the disk;
- iii. determining a highest disk maximum position which is the highest disk maximum position measured during all of the test cycles conducted;
- and
- iv. determining a current disk minimal position which is the lowest position at which the disk falls within the test chamber during the last test cycle and a lowest disk minimal position which is the lowest disk minimal position measured during all of the test cycles conducted;
- d. calculating a reference disk-span being equal to the highest disk maximum position minus a lowest disk minimal position;
- e. identifying a reference for enabling disk minimum position being equal to the lowest disk minimal position;
- f. calculating a reference for enabling integration of disk minimum position equaling the reference disk minimum position+(Y %×the reference disk-span);
- wherein Y % is a value between 0 and 100%;
- g. subtracting the lowest disk minimal position from the current disk minimal position to calculate a change in minimal position;
- h. comparing the change in minimal position to the reference for enabling integration of disk minimum position;
- wherein, if the change in minimal position is less than the reference for enabling integration of disk minimum position, a clot will not be indicated to be detected and when the change in minimal position is greater than the reference for enabling integration of disk minimum position, then a disk change value is set to be the change in minimal position;
- i. adding each disk change value of all conducted test cycles to calculate a distance minimum sum;
- and
- j. during at least one specified test period, comparing the distance minimum sum to a clot detection reference;
- wherein if the distance minimum sum is greater than the clot detection reference, a clot is indicated to be detected;
- wherein if the distance minimum sum is not greater than the clot detection reference, a clot is not indicated to be detected.
18 more elements
A method of detecting the formation of a clot in a fluid sample during a coagulation test phase including one or more test periods, the method comprising:
- a. providing a test chamber having a top and a bottom and further providing a disk positioned within the test chamber;
- b. filling the test chamber with the fluid sample;
- c. conducting a first test cycle including:
- i. positioning the disk at a first disk maximum position within the test chamber;
- wherein the first disk maximum position is the highest point at which the disk is positioned during the first test cycle;
- ii. measuring the first disk maximum position;
- iii. dropping the disk;
- and
- iv. determining a first disk minimal position which is the lowest point at which the disk falls within the test chamber during the first test cycle;
- d. conducting a second test cycle including:
- i. positioning the disk at a second disk maximum position within the test chamber;
- wherein the second disk maximum position is the highest point at which the disk is positioned during the second test cycle;
- ii. measuring the second disk maximum position;
- iii. dropping the disk;
- and
- iv. determining a second disk minimal position which is the lowest point at which the disk falls within the test chamber during the second test cycle;
- e. conducting a third test cycle including:
- i. positioning the disk at a third disk maximum position within the test chamber;
- wherein the third disk maximum position is the highest point at which the disk is positioned during the third test cycle;
- ii. measuring the third disk maximum position;
- iii. dropping the disk;
- and
- iv. determining a third disk minimal position which is the lowest point at which the disk falls within the test chamber during the third test cycle;
- f. calculating a reference disk-span being equal to the highest of the first, second and third disk maximum positions minus the lowest of the first, second and third disk minimal positions;
- g. identifying a reference disk minimum position being equal to the lowest of the first, second and third disk minimal positions;
- h. calculating a clot detection reference being equal to the reference disk minimum position+(X %×the Reference Disk-Span);
- wherein X % is a value between 0 and 100%;
- i. conducting a fourth test cycle including:
- i. positioning the disk at a fourth disk maximum position within the test chamber;
- wherein the fourth disk maximum position is the highest point at which the disk is positioned during the fourth test cycle;
- ii. measuring the fourth disk maximum position;
- iii. dropping the disk;
- and
- iv. determining a fourth disk minimal position which is the lowest point at which the disk falls within the test chamber during the fourth test cycle;
- and
- j. comparing the fourth disk minimal position to the clot detection reference;
- and
- k. repeating steps j(i-iv) to conduct fifth and sixth test cycles and comparing the fifth and sixth disk minimum positions to the clot detection reference;
- and
- l. either declaring a clot to be detected when all of the fourth-sixth disk minimum positions are greater than the clot detection reference or not indicating a clot to be detected when any of the fourth-sixth disk minimum positions are not greater than the clot detection reference.
37 more elements
Dependencies are inferred from the claim text.