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BACKGROUND: Platelet (PLT) collection and storage affect the functional capacity of PLTs in PLT concentrates (PCs). Therefore, PLTs' functional quality should be studied before transfusion. STUDY DESIGN AND METHODS: PCs (n = 15) were collected by a standard apheresis procedure (Trima, Gambro BCT) and were stored for 7 days. Samples were taken to assess PLT adhesion and aggregate formation by a cone and plate analyzer (Impact-R, DiaMed) on Days 1, 3, 5, and 7 after harvesting. This device allows testing PLT function under high-shear stress close to physiologic conditions. Concomitantly, P-selectin expression and the residual responsiveness to TRAP-6 were determined by flow cytometry. RESULTS: PLT adhesion, as measured by surface coverage, decreased during the entire observation period; likewise, the size of aggregates was significantly lower on Days 5 and 7 compared to Day 1 (p < 0.02). P-selectin expression increased from Day 5 to Day 7 (p < 0.04), whereas TRAP-6–inducible expression remained stable until Day 5 of storage and decreased significantly on Day 7 (p = 0.04). CONCLUSIONS: Our results show that high-shear–induced PLT adhesion and aggregation on the polystyrene surface deteriorate upon storage, suggesting decreased PLT function in vivo. Thus, the Impact-R may be a useful tool to assess the functional capacity of PLTs under various PLT harvesting and storage procedures. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bernard-Soulier syndrome (BSS) patients may repeatedly require transfusion of platelets (PLTs). The hemostatic competence of transfused PLTs requires monitoring. STUDY DESIGN AND METHODS: Flow cytometry and a cone and plate(let) analyzer (Impact-R, DiaMed) were used to monitor survival and function of transfused PLTs in a 7-year-old girl with BSS undergoing surgery. Flow cytometry was applied to differentiate autologous PLTs from transfused PLTs by staining for CD42b. The Impact, which measures PLT adhesion and aggregation in response to high shear stress, was used to evaluate PLT function. RESULTS: Transfused PLTs were detectable by flow cytometry for 1 week after transfusion. While the patient’s PLTs did not respond to high shear stress before transfusion, a normal response was documented by the Impact on the day after transfusion and 1 week thereafter. CONCLUSION: Transfused PLTs were detectable by flow cytometry, and their functional activity was demonstrated by the Impact. [ABSTRACT FROM AUTHOR]