What is PRP, and what happens at the visit?

How does your blood become concentrated PRP?

The clinic draws a small amount of blood and spins it in a machine. Spinning separates the blood into layers. The clinic keeps a layer with many platelets for the planned treatment.

Some PRP keeps more white cells, while some has more red cells left in it. White cells may add soreness afterward, and red cells can irritate the treated area. Because clinics make different mixtures, studies may not be testing the same PRP.

Why can't one study answer every PRP question?

A knee supports body weight, while a shoulder tendon, the cord joining muscle to bone, helps move the arm. PRP that seems useful for one part may not help the other. The cause of soreness also changes which care makes sense.

Lab and animal work can show what platelets release after blood is spun. Only human studies can tell whether people walk, sleep, or move with less soreness. Even those studies can't promise how one person will feel.

What will QC Kinetix explain before treatment?

At QC Kinetix, medical providers may turn blood drawn there into PRP during your visit; these are the people who examine you and direct your care. Ask which sore part will receive the treatment and how the exam found it. Also ask what care comes before and after PRP.

Before the visit, write down aspirin, blood thinners, and every other medicine you take, along with each dose and the reason your doctor gave it to you for your health. Aspirin and some swelling medicines can change how platelets clump, while blood thinners can raise bleeding. Keep taking each prescribed drug unless the doctor who ordered it agrees to a change.

Sources

1. The American Academy of Physical Medicine and Rehabilitation convened a technical expert panel that ran a structured literature review (2023, updated through June 2025) and a modified Delphi process, and issued five evidence-based clinical recommendations plus 11 consensus-based best practices for PRP in knee osteoarthritis. The statement is explicit that orthobiologic therapies 'remain an evolving area of practice' and that robust, dose-dependent randomized controlled trials are still needed to establish PRP's clinical effects.

   Borg-Stein J, Jayaram P, Colorado BS, et al. — AAPM&R guidance statement on platelet rich plasma for knee osteoarthritis. PM&R, 2026. DOI: 10.1002/pmrj.70144.

2. A systematic review and meta-analysis of adverse events in randomized trials of intra-articular PRP for knee osteoarthritis found PRP associated with mild, transient adverse events - knee pain and swelling - that typically resolve without intervention, and more frequent with LEUKOCYTE-RICH formulations. Leukocyte-poor PRP had a safety profile similar to hyaluronic acid. Knee stiffness was more frequent with PRP than with normal saline (P=.031). No severe adverse events were reported in any group.

   Nakagawa HF, Kim J, Rabinowitz J, et al. — Assessment of adverse events and safety associated with intra-articular platelet-rich plasma injections compared to other injectates for knee osteoarthritis: A systematic review and meta-analysis. PM&R, 2026. DOI: 10.1002/pmrj.70141.

3. A prospective fixed-sequence controlled laboratory study in healthy men found that daily low-dose aspirin significantly reduced release of VEGF, PDGF-AB and TGF-beta1 from freshly isolated leukocyte-rich PRP when activated with arachidonic acid. This is the mechanistic basis for the routine instruction to review antiplatelet and NSAID use before a PRP draw - and the authors noted clinical studies are still needed to establish how much this matters in vivo.

   Jayaram P, Yeh P, Patel SJ, et al. — Effects of Aspirin on Growth Factor Release From Freshly Isolated Leukocyte-Rich Platelet-Rich Plasma in Healthy Men: A Prospective Fixed-Sequence Controlled Laboratory Study. American Journal of Sports Medicine, 2019. DOI: 10.1177/0363546519827294.

4. In the RESTORE trial - the largest placebo-controlled PRP trial in knee osteoarthritis - 288 adults aged 50+ with symptomatic Kellgren-Lawrence grade 2-3 medial knee OA received three weekly intra-articular injections of leukocyte-poor PRP from a commercial system or saline placebo. At 12 months the mean change in knee pain was -2.1 points with PRP versus -1.8 with saline (difference -0.4; 95% CI -0.9 to 0.2; P=.17) against a minimum clinically important difference of 1.8, and the change in medial tibial cartilage volume was -1.4% versus -1.2% (difference -0.2%; 95% CI -1.9% to 1.5%; P=.81). Twenty-nine of 31 prespecified secondary outcomes showed no significant between-group difference. The authors concluded the findings do not support use of PRP for knee OA.

   Bennell KL, Paterson KL, Metcalf BR, et al. — Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial. JAMA, 2021. DOI: 10.1001/jama.2021.19415.

5. The devices used to spin PRP at the point of care are cleared by FDA as clinical centrifuges, product code JQC, a Class I device under 21 CFR 862.2050 - for example the Biomet GPS Platelet Separation Kit (K030555, cleared 2003) and the Harvest SmartPrep2 / SmartPrep Platelet Concentration System (K103340, cleared 2010). That clearance covers the equipment that separates blood. It is not an FDA approval of platelet-rich plasma as a treatment for osteoarthritis, tendinopathy or any other orthopedic condition, and copy must never blur the two.

   U.S. Food and Drug Administration (Center for Devices and Radiological Health) — 510(k) Premarket Notification database and Product Classification: JQC, Centrifuges (Micro, Ultra, Refrigerated) For Clinical Use, 21 CFR 862.2050. FDA accessdata (CDRH device databases), 2003.