Medtronic, Inc.

Medtronic Vascular, Inc.

Lawrence Erickson

Charlene X Yuan

Trevor Huang

Daniel Cheek

Tessy Kanayinkal

Craig D Petersen

Charlene Yuan

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.

Clot detection methods for clotting time testing

Activated clotting time (ACT) tests detect blood clotting time based on the viscosity changes of a test sample, using a ferromagnetic washer lifted to the top of a test chamber and then dropped from the top via gravity; a drop time greater than a preset threshold value indicates clotting of the test sample. Blood samples which have high levels of heparin usually produce very weak clots that may easily be destroyed by the lifting movement of the washer. But if the clot threshold is set low to detect the weak clots, false detections occur during early testing cycles when activators are not fully suspended during the mixing cycle. Improved algorithms for lifting the washer and adjusting over time enable accurate detection of weak clots.

Clot protection and detection algorithm for activated clotting time testing

Multi-zone falling washer blood clot detection

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Brooklyn Park, MN, United States of America

Lawrence Erickson