DESCRIPTION (Verbatim From Applicant's Abstract):This phase II application is for further development, optimization, and clinical testing of a platelet function assay called the light scattering whole blood aggregometer (LSWBA). The concept of utilizing differential light scattering for the detection of platelet aggregates in whole, undiluted blood was proven as part of Phase I research. Further, when the LSWBA was compared with the existing laboratory-based aggregometers, the results documented that the assessment of platelet function with LSWBA was qualitatively similar to the existing devices. The most stifling limitation of the platelet aggregometers currently on the market is that blood samples have to be sent to the laboratory for the assessment of platelet function. Assessment of platelet function at the point of care may greatly improve antiplatelet therapy by providing clinicians the opportunity to tailor drug regimen to suit individual patient needs. The LSWBA addresses all the logistical and conceptual limitations of the existing devices and is poised to emerge as a true bedside diagnostic tool for the assessment of platelet function. The availability of such a device will enable physicians to fine-tune drug therapy and to minimize the risk of thrombosis or bleeding. The Phase II work is proposed to: 1) further optimize and standardize the sample holder which is an essential part of the LSWBA, 2) establish a databank of agonist dose-responses to later identify abnormal platelet function and, 3) test the point-of care utility of the LSWBA in the clinical environment. PROPOSED COMMERCIAL APPLICATION: This research will lead to a prototype point-of-care diagnostic tool to assess platelet function. This tool will permit physicians to tailor prophylactic and therapeutic antiplatelet drug regimen in a manner that was not possible before. A more controlled antiplatelet therapy will not only minimize the risk of adverse effects but will also reduce patient morbidity and will result in an overall improved clinical outcome. Current estimates suggest a market potential of approximately $100 million/year for equipment and supplies for a point-of-care whole blood aggregometer.