PREPAReS study

Pathogen Reduction Evaluation & Predictive Analytical Rating Score

Study Title

Pathogen Reduction Evaluation & Predictive Analytical Rating Score: The PREPAReS Study. Clinical effectiveness of standard versus pathogen-reduced buffy coat-derived platelet concentrates in plasma.


A new method was developed for pathogen-reduction of platelet concentrates to inactivate micro-organisms that might be present. When riboflavin (vitamin B2) is added to the platelet concentrate, and then illuminated with UV-B light, the pathogen-reduced platelet concentrate is then ready for transfusion use. There are few clinical data on these treated platelet concentrates, and thus a clinical study is needed.


In this two-armed study, treated platelet concentrates are compared with standard untreated ones. From these platelet concentrates a sample will be taken immediately before issuing to the hospital, and various in vitro tests will be performed to link laboratory results with clinical outcomes. Another objective for laboratory study is the possibility that the treatment may result in less alloimmunization in the recipient, which in turn will result in fewer patients that become unresponsive to platelet transfusions. In the hospital, the bleeding rate, increments after transfusion and adverse events will be compared.


A randomized controlled clinical trial to study the effectiveness of pathogen-reduced platelet concentrates in plasma, stored for up to 7 days, and compare these with untreated platelet concentrates in plasma, also stored for up to 7 days.

Additional Information

Information on the study design, study population, and study parameters/endpoints, can be found here:
The last of 567 patients was enrolled in the PREPAReS study in May 2016. Data is anticipated to be released in late 2016 or early 2017.