In the last few years, there has been a significant increase in the number of manuscript submissions related to Platelet-Rich Plasma (PRP) to I Platelets i . Defining the cellular and bioactive factor contents of different PRP preparations is therefore essential to understand the variables associated with the potential biological activity/efficacy of PRP preparations [[7]]. A measure of quality of the PRP preparation (e.g. cellular content, platelet activation status, platelet specific proteins and growth factor content). [Extracted from the article]