Platelet concentrate functionality assessed by thromboelastography or rotational thromboelastometry

There is poor correlation between in vivo platelet concentrate (PC) transfusion outcome and in vitro tests, which typically do not test the functional effectiveness of platelets (PLTs), but rather measure PLT characteristics. We hypothesize that the application of thromboelastography (TEG) or rotational thromboelastometry (ROTEM) to evaluate the procoagulant activity of stored PLTs can predict PLT quality and, ultimately, distinguish among hyper- and nonresponsive PCs. Additionally, we hypothesize that due to their procoagulant properties, PLT microvesicles (PMVs) contribute to the clot signature in these methods.

After the TEG assays were validated, buffy coat PCs were evaluated during the storage time and reconstituted with frozen plasma to different PLT concentrations. Poor quality PCs were generated and assessed by TEG and other in vitro tests. The contribution of PMVs to the TEG clot signature was assessed.

Hemostatic analysis showed no significant change in maximum amplitude (MA) during storage of PCs up to Day 10. On Day 8 of storage, PCs that had been manipulated to have poor quality showed a significant decrease in MA. PMV-rich samples contributed to a significant increase in MA, and PMV count showed a significant correlation with maximum clot formation (r = 0.51, p < 0.01).

TEG was optimized for use with buffy coat PCs, although it was found to lack sensitivity to detect normal storage-related quality changes. Hemostatic measurement was sufficiently sensitive to dissect PLT and PMV contributions to clot formation and to detect PCs stored under poor conditions.