What is PRP and PRF?
Platelet-Rich Plasma, or PRP, is an autologous biologic derived from our own blood. The treatment is prepared by taking a sample of blood and spinning it down in a centrifuge to concentrate components necessary for accelerated healing and regeneration. These components include platelets and growth factors that stimulate and promote the natural healing cascade. PRP has been used in a variety of medical fields for decades, with Harvest PRP being the first commercial point-of-care system in Canada.
Platelet-Rich Fibrin, or PRF, is also an autologous biologic. It works in a similar manner as PRP, with blood being drawn from a patient, and subsequent centrifugation. However, there are some key differences in their preparation. In PRP, an anti-coagulant is used to prevent clotting during the blood draw and spin down phases. For example, the anti-coagulant in Harvest PRP, ACD-A, has been used by blood banks for decades and is proven to be a safe and effective solution for preserving platelet integrity and increasing concentration. However, an anti-coagulant is not added in the preparation of PRF. Another key difference is the centrifugation step. In PRF, the blood sample is spun down in a single-spin system and at a slower speed, which combined with the lack of anticoagulant causes the solution to form a viscous "fibrin-gel".
Platelet Concentration
It's been long understood that the concentration of platelets in a PRP solution plays a critical role in the healing process. Platelets release several important growth factors including PDGF, TGF-B, VEGF, and SDF-1a. These factors play pivotal roles in modulating inflammation, angiogenesis, and tissue regeneration (1,2,3,4). Higher platelet concentrations of a solution allow for more growth factors to be released, in turn resulting in a stronger healing response. Studies indicate that a platelet concentration of at least 4x above baseline is required for an optimal healing response (5,6,7). Any concentrations lower than 4x above baseline, can technically be referred to as platelet poor as it does not provide amble growth factors for healing.
While not all PRP systems are created equal, for example the Harvest PRP system delivers high platelet and growth factor concentrations in the 5-7x range above baseline. One recent independent study verified the Harvest PRP system to increase platelet concentrations more than 7x above baseline (8). These high levels of concentration can be attributed to system design (double-spin system and unique PRP kit), as well as the use of the ACD-A anticoagulant.
On the other hand, commercial PRF systems are not able to reach high concentrations of platelet and growth factor. Due to utilizing a single-spin system, as well as a much slower spin speed, PRF can only concentrate platelets to an average of less than 1.9x above baseline (9). This is an important finding as some websites and online blog posts will make claims that PRF can reach over 10x above baseline! This is simply not the case.
Replicability and Ease of Injection
Anticoagulants, such as ACD-A, are an important step in the preparation of a platelet rich solution to ensure the replicability of each treatment.
ACD-A ensures replicability and ease of injection by preventing coagulation during PRP preparation. Coagulation can occur throughout the preparation process, from drawing the blood, to spinning it down and injecting it back into the patient. The formation of a blood clot (or a “fibrin clot”) during PRP preparation results in a final product that is unusable. In turn, another blood draw will need to be taken from the patient, wasting both the clinics and patient time. Thus, without the use of an anticoagulant, one cannot ensure consistent replicability.
The use of an anticoagulant also ensures the ease of injection with each treatment. After producing a final PRF product, you have a limited time frame in which you need to inject the patient before coagulation begins. On the other hand, ACD-A provides a clinician several hours before the PRP needs to be injected back into the patient.
Structure
Unlike PRP, PRF provides a more viscous and solid structure due to the slow spin speed of the centrifuge. Due to its gel-like structure, PRF’s effects may be more localized and growth factors released over a longer period of time than all at once with PRP. However, this extended release is not necessarily beneficial, as evidence on the matter is limited and inconclusive.
When it comes to some cosmetic procedures, like face lifts, the thicker PRF can give the appearance of instantaneous results compared to PRP by providing immediate "filling" up the skin. As well, in some procedures where you want the PRF to remain exactly in one spot, a PRF-type solution can be beneficial.
However, considering PRF cannot reach significant levels of platelet concentrations that PRP can, the long-term benefits of PRP heavily outweigh PRF. In cosmetics this can mean increased elastin and collagen production to rejuvenate the skin, and increased vascularization to create a healthy scalp environment to prevent hair loss. In sports medicine and MSK procedures, this higher platelet count translates to greater pain relief and healing capacity.
Conclusion
While PRF can offer a more solid structure, there are several sacrifices made in doing so. PRF exhibits lower platelet and growth factor concentration, inconsistencies between treatments, and creates an error-prone treatment protocol with the chance of fibrin clots. Until a commercial system can create a PRF solution that can overcome these barriers, high concentration PRP systems should remain as your first choice for regenerative biologic treatments.
References
Tang Y, Yeaman M, Selsted M. Antimicrobial peptides from human platelets. Infect Immun. 2002;70(12):6524-6533
Drago L, Bortolin M, Vassena C, et al. Antimicrobial activity of pure platelet-rich plasma against microorganisms isolated from oral cavity. BMC Microbiol. 2013:13(47):1-5.
Amable P, Carias R, Teixeira M, et al. Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors. Stem Cell Res Ther. 2013;4(3):67.
Ríos D, López C, Carmona J. Platelet-rich gel supernatants stimulate the release of anti-inflammatory proteins on culture media of normal equine synovial membrane explants. Vet Med Int. 2015;2015:547052.
Marx, RE. Platelet-Rich Plasma: Evidence to support its use. J Oral Maxillofac Surg 2004; 62:489-496.
Cole B, Karas V, Hussey K, Pilz K, Fortier L. Hyaluronic Acid Versus Platelet-Rich Plasma: A prospective, double-blind randomized controlled trial comparing clinical outcomes and effects on intra-articular biology for the treatment of knee OA. Am J Sports Medicine. 2017. 45(2):339-34.
Gentile P, Garcovich S. Systematic Review—The Potential Implications of Different Platelet-Rich Plasma (PRP) Concentrations in Regenerative Medicine for Tissue Repair. Int J of Mol Sci. 2020. 21:5702.
Marathe, A., Patel, S., Song, B., Sliepka, J., Shybut, T., Lee, B., & Jayaram, P. (2022). Double-Spin Leukocyte-Rich Platelet-Rich Plasma Is Predominantly Lymphocyte Rich With Notable Concentrations of Other White Blood Cell Subtypes. Arthroscopy, Sports Medicine, And Rehabilitation, 4(2), e335-e341. doi: 10.1016/j.asmr.2021.10.004
Pavlovic, V., Ciric, M., Jovanovic, V., & Stojanovic, P. (2016). Platelet Rich Plasma: a short overview of certain bioactive components. Open Medicine, 11(1), 242-247. doi: 10.1515/med-2016-0048
This blog post provides general information to help the reader better understand regenerative medicine, musculoskeletal health, and any related subjects. The views and opinions expressed in this post are those of the author and may not reflect the views and opinions of MDBiologix. All content provided in this blog, website, or any linked materials, including text, graphics, images, patient profiles, outcomes, and information, are not intended and should not be considered or used as a substitute for medical advice, diagnosis, or treatment. Please always consult with a professional and certified healthcare provider to discuss if any treatment is right for you.