Platelet cryopreservation has been investigated for several decades as an alternative to
room temperature storage of platelet concentrates. The use of dimethylsulfoxide as a cryoprotectant
has improved platelet storage and cryopreserved concentrates can be kept at −80 °C for two years.
Cryopreserved platelets can serve as emergency backup to support stock crises or to disburden
difficult logistic areas like rural or military regions. Cryopreservation significantly influences
platelet morphology, decreases platelet activation and severely abrogates platelet aggregation.
Recent data indicate that cryopreserved platelets have a procoagulant phenotype because thrombin
and fibrin formation kicks in earlier compared to room temperature stored platelets. This happens
both in static and hydrodynamic conditions. In a clinical setting, low 1-h post transfusion recoveries
of cryopreserved platelets represent fast clearance from circulation which may be explained by
changes to the platelet GPIbα receptor. Cryopreservation splits the concentrate in two platelet
subpopulations depending on GPIbα expression levels. Further research is needed to unravel its
physiological importance. Proving clinical efficacy of cryopreserved platelets is difficult because of
the heterogeneity of indications and the ambiguity of outcome measures. The procoagulant
character of cryopreserved platelets has increased interest for use in trauma stressing the need for
double-blinded randomized clinical trials in actively bleeding patients
