Rapid Monitoring of Antithrombin Agents

A functional assay system for monitoring antithrombin drugs, such as recombinant hirudin andhirudin analogs, in patients will be developed. This assay system will be based on a novel dry reagentparamagnetic particle-based assay technology that has recently been applied successfully to wholeblood, bedside monitoring of prothrombin time and activated partial thromboplastin time testing. Thedry reagent assay consists of paramagnetic iron oxide particles whose oscillations in an imposedmagnetic field will be dampened by the formation of a fibrin clot around the particles. The clotting timein turn is related to the concentration of thrombin inhibitor present in the blood sample. Specific aimsinclude: (1) compare the aPPT-based assay with a thrombin-based test system; (2) refine the prototypeaPPT-based hirudin assay or thrombin time-based assay by test card optimization and testing; (3) developalgorithms for rapid calibration and standardization to a reference method; and (4) study the effects ofpotential influencing factors on the assay and determine performance characteristics. Introduction ofa rapid, convenient assay system for antithrombin drugs at the patient point-of-care could provide resultsearlier than existing and newly-emerging laboratory methods and could serve as an important diagnosticguide during therapy.