4.1 Autologous PRP and platelet gels are utilized in a wide range of orthopedic, sports medicine, regenerative medicine, and surgical applications (3-5). PRP and platelet gels are layered, sprayed, injected, molded, or packed, alone or in combination with graft material or TEMPs, into a variety of anatomical sites, tissues, and voids (3, 6). These platelet concentrates can provide an assortment of bioactive molecules, cells, and physical properties that are potentially attractive for promoting healing and other cell therapy applications (7). Unfortunately, the term “platelet-rich plasma” or “PRP,” which is ubiquitous in early and contemporary medical literature related to a variety of platelet concentrates, only unambiguously denotes one critical parameter of a platelet suspension—increased platelet concentration. Without further context, this common description of PRP offers no information about other important physical and cellular aspects of platelet concentrations. As scientific and clinical understanding of PRP and other cellular therapies increases standardization of nomenclature and terminology is critical for defining key properties, standardizing processing parameters and techniques, and developing repeatable assays for quality assurance and scientific evaluation (5, 8-13). This guide outlines basic guidelines to describe key properties of unique PRP and platelet gel formulations in a standardized fashion. Reliable, standardized descriptions can provide valuable context to PRP end users, such as clinicians seeking a PRP or platelet gel with certain biological attributes or scientific investigators seeking to duplicate a published formulation or to correlate a given PRP or platelet gel feature to other biological properties or outcomes.

1.1 This guide defines terminology and identifies key fundamental properties of autologous platelet-rich plasma (PRP) and PRP-derived platelet gels intended to be used for tissue engineered medical products (TEMPS) or for cell therapy applications. This guide provides a common nomenclature and basis for describing notable properties and processing parameters for PRP and platelet gels that may have utility for manufacturers, researchers, and clinicians. Further discussion is also provided on certain aspects of PRP processing techniques, characterization, and quality assurance and how those considerations may impact key properties. The PRP characteristics outlined in this guide were selected based n a review of contemporary scientific and clinical literature but do not necessarily represent a comprehensive inventory; other significant unidentified properties may exist or be revealed by future scientific evaluation. This guide provides general recommendations for how to identify and cite relevant characteristics of PRP, based on broad utility; however, users of this standard should consult referenced documents for further information on the relative import or significance of any particular PRP characteristic in a particular context.

1.2 The scope of this guide is confined to aspects of PRP and platelet gels derived and processed from autologous human peripheral blood. Platelet-rich plasma, as defined within the scope of this standard, may include leukocytes.

1.3 The scope of this document is limited to guidance for PRP and platelet gels that are intended to be used for TEMPS or for cell therapy applications. Processing of PRP, other platelet concentrates or other blood components for direct intravenous transfusion is outside the scope of this guide. Apheresis platelets and other platelet concentrates utilized in transfusion medicine are outside the scope of this document. Production of PRP or platelet gels for diagnostic or research applications unrelated to PRP intended for TEMPS or cell therapy is also outside the scope of this guide. Fibrin gels devoid of platelets are also excluded from discussion within this document.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.