r 308 COPYRIGHT © 2012 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED .•a i« Platelet-Rich Plasma Differs According to Preparation Method and Human Variability Augustus D. Mazzocca, MS, MD, Mary Beth R. McCarthy, BS, David M. Chowaniec, BS, Mark P. Cote, DPT, Anthony A. Romeo, MD, James P. Bradley, MD, Robert A. Arciero, MD, and Knut Beitzel, MD Investigation performed at the Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut Background: Varying concentrations of blood components in platelet-rich plasma preparations may contribute to the variable results seen in recently published clinical studies. The purposes of this investigation were (1) to quantify the level of platelets, growth factors, red blood cells, and white blood cells in so-called one-step (clinically used commercial devices) and two-step separation systems and (2) to determine the influence of three separate blood draws on the resulting components of platelet-rich plasma. Methods: Three different platelet-rich plasma (PRP) separation methods (on blood samples from eight subjects with a mean age [and standard deviation] of 31.6 ± 10.9 years) were used: two single-spin processes (PRPLp and PRPHp) and a double-spin process (PRPDs) were evaluated for concentrations of platelets, red and white blood cells, and growth factors. Additionally, the effect of three repetitive blood draws on platelet-rich plasma components was evaluated. Results: The content and concentrations of platelets, white blood cells, and growth factors for each method of separation differed significantly. All separation techniques resulted in a significant increase in platelet concentration compared with native blood. Platelet and white blood-cell concentrations of the PRPHp procedure were significantly higher than platelet and white blood-ceil concentrations produced by the so-called single-step PRPLp and the so-called two-step PRPDS procedures, although significant differences between PRPLPand PRPDSwere not observed. Comparing the results ofthethree blood draws with regard to the reliability of platelet number and cell counts, wide variations of intra-individual numbers were observed. Conclusions: Single-step procedures are capable of producing sufficient amounts of platelets for clinical usage. Within the evaluated procedures, platelet numbers and numbers of white blood ceils differ significantly. The intra-individual results of platelet-rich plasma separations showed wide variations in platelet and cell numbers as well as levels of growth factors regardless of separation method. Clinical Relevance: The variability of components and its effects on dosage should be considered in single or con- secutive treatments of platelet-rich plasma. Significant differences in components were observed in different separation methods and may have specific results on treated tissue. O ver the past decade, platelet-rich plasma has gained increased attention in orthopaedic sports medicine. Several investigators have advocated the use of platelet- rich plasma in the management of bone, muscle, tendon, and cartilage injury1"3. Platelets contain growth factors in their alpha- granules, such as transforming growth factor-beta (TGF-(3), fibroblast growth factor-2 (FGF-2), platelet-derived growth factors (PDGF-AB), insulin-like growth factor-1 (IGF-1), epi- dermal growth factor (EGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF-A), which are thought to produce beneficial effects on the hearing process. The ultimate goal of platelet-rich plasma treatment is to concentrate these growth factors and reintroduce them to a site of injury1. Despite the growing popularity of platelet-rich plasma treatment, little is known regarding the specifics of plasma preparations or the devices used in their production1"3. Platelet- Disclosure: One or more of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of an aspect of this work. In addition, one or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months priorto submission of this work, with an entity in the biomedicai arena that could be perceived to influence or havethe potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article. J Bone Joint Surg Am. 2012;94:308-16 • http://dx.doi.Org/10.2106/JBJS.K.00430.