How to Make PRF: A Step-by-Step Preparation Process

Platelet-rich fibrin is made by drawing a patient’s own blood into additive-free tubes and spinning it in a centrifuge at relatively low speed, typically for about eight minutes. Because PRF relies entirely on the blood’s natural clotting cascade rather than added chemicals, the process is simpler than older platelet concentrates, but the details matter far more than they might appear to. Small differences in centrifuge speed, rotor type, and especially timing can mean the difference between a dense, growth-factor-rich clot and a flimsy one that falls apart on the surgical tray.

Why No Additives Are Needed

The defining feature of PRF, and the reason it is sometimes called a “second-generation” platelet concentrate, is that the blood is collected without anticoagulants or any other additives. Older preparations like platelet-rich plasma (PRP) use anticoagulant tubes and then require a separate activating agent, usually bovine thrombin or calcium chloride, to trigger clotting at the point of use. PRF skips both steps. When blood enters a plain glass or glass-coated tube with no anticoagulant, clotting starts immediately upon contact with the tube wall. The centrifuge then separates the blood components while that natural clot is still forming, producing a fibrin matrix packed with platelets, white blood cells, and their associated growth factors. This is why the clock starts ticking the moment blood leaves the vein.

The Blood Draw and the 90-Second Rule

PRF preparation begins with a standard venipuncture, usually from the antecubital vein at the inside of the elbow. The number of tubes drawn depends on what the clinician needs: a single extraction socket might call for one or two tubes, while a larger bone graft could require six or more. Glass or glass-coated plastic tubes without anticoagulant are standard.

The critical detail here is speed. Because clotting begins the instant blood touches the tube wall, centrifugation should start within about 90 to 120 seconds of the blood draw.¹ If you wait too long, the fibrin polymerizes in a disorganized way throughout the tube, and the centrifuge cannot cleanly separate the layers. The result is a small, poor-quality clot with fewer trapped cells. Clinicians who prepare PRF routinely describe this as the single most common source of failure: the blood sits on the counter for a few minutes while someone sets up the centrifuge, and by then it is too late to get a good product. Pre-setting the centrifuge before the blood draw is a practical habit that matters more than the exact spin protocol chosen.

Centrifugation Settings for Solid PRF

Once the tubes are loaded, the centrifuge separates the blood into three visible layers. The bottom layer is packed red blood cells. The top layer is a straw-colored, cell-poor plasma. Between them sits the PRF clot itself: a dense fibrin network loaded with platelets, leukocytes, and growth factors. A thin transition zone called the buffy coat sits right at the junction of the clot and the red cell layer, and it contains the highest concentration of cells.

The original protocol developed by Joseph Choukroun used a fixed-angle centrifuge at roughly 400g (about 3,000 RPM on many tabletop models) for 10 minutes. Since then, researchers have tested dozens of variations. A study evaluating 24 different centrifugation protocols found that optimal settings for solid PRF fell between 400 and 700g for eight minutes, with the highest concentration of platelets and leukocytes actually appearing at a lower force of 200g for five minutes.² An expert dermatology group recommended the A-PRF+ protocol of 200g for eight minutes for solid PRF.¹

A note on units: you will see protocols described in RPM and in g-force, and these are not interchangeable. The g-force depends on both RPM and the radius of the centrifuge rotor, so a protocol that calls for 2,700 RPM on one machine might produce a completely different g-force on another with a different rotor size. Indian studies, for instance, commonly report using centrifuges with a rotor radius of 7.5 to 12 cm, which at common RPM settings produce g-forces in the 700 to 1,000g range.³ If you are following a published protocol, always verify the g-force, not just the RPM, for your specific machine.

Horizontal Versus Fixed-Angle Centrifuges

This is one of the more debated technical points in PRF preparation. In a fixed-angle centrifuge, the tubes sit at an angle (commonly around 33 to 45 degrees from vertical) throughout the spin. In a horizontal (swing-out bucket) centrifuge, the tubes start upright and swing outward to a fully horizontal position once the rotor reaches speed.

The practical difference shows up in how cells distribute within the clot. With fixed-angle spinning, cell separation follows the angle of the rotor, creating a sloped boundary between layers. Red blood cells, leukocytes, and platelets tend to accumulate along the tube’s outer wall rather than distributing evenly. Horizontal centrifugation produces a much smoother, more uniform cell distribution throughout the PRF clot.⁴ One study found that horizontal centrifugation roughly doubled the release of PDGF (a key wound-healing growth factor) and increased FGF release by about 70% compared to fixed-angle spinning.⁵

That said, the picture is not entirely one-sided. A separate study comparing centrifuge types at standardized g-force found no significant differences in cell density, growth factor release over seven days, or cell viability between fixed-angle and swing-out rotors.⁶ The researchers concluded that applied g-force and spin time are the dominant variables, and rotor type matters less when those are properly controlled. For clinicians choosing equipment, a horizontal centrifuge may offer a slight edge, but investing in one is not mandatory if you already have a well-calibrated fixed-angle machine. The expert recommendation still leans toward horizontal models when possible.¹

The Low-Speed Centrifugation Concept

A shift in thinking over the past several years has pushed PRF protocols toward lower and lower centrifuge speeds. The logic is counterintuitive: spin harder and you pack more cells into a tight buffy coat, but you also trap fewer of them in the usable fibrin clot. Spin gentler and more platelets, leukocytes, and their growth factors remain suspended within the fibrin matrix where they can actually do their job.

Research backing this idea showed that systematically reducing the relative centrifugal force led to significant increases in leukocyte and platelet counts within the PRF product, along with higher concentrations of growth factors like VEGF and TGF-β1.⁷ Follow-up work demonstrated that these lower-speed PRF clots also increased fibroblast migration and proliferation in lab settings, which is directly relevant to how tissue actually heals.⁸ This body of work is the basis for protocols like A-PRF+ (200g for eight minutes), which deliberately uses a much lower force than older recipes that called for 400g or more.

The trade-off is clot size. Lower g-forces sometimes yield a slightly smaller fibrin clot because less plasma is driven upward. For procedures that need large membranes, such as covering a bone graft, some clinicians compromise with a moderate force in the 400 to 700g range to get a balance of clot size and cell content.

Removing and Handling the Clot

After centrifugation, you remove the tube from the centrifuge and will see the three distinct layers. The PRF clot is gently pulled or squeezed out of the tube using sterile forceps or a dedicated clot-retrieval instrument. It emerges as a soft, gelatinous mass attached to a small red thrombus at its base. The red portion is trimmed away, typically about two millimeters into the clot, because cutting too far up discards the cell-rich buffy coat layer where platelets and leukocytes concentrate most heavily.

For many applications, the clot is then compressed between two flat plates to form a membrane. Dedicated devices known as PRF boxes are designed for this: they apply gentle, even pressure and drain away the excess serum without crushing the fibrin network or squeezing out the trapped cells. The resulting membrane is firm enough to handle with instruments and can be cut, layered, or sutured over a surgical site. If you simply smash the clot with gauze or a heavy instrument, you lose much of the cellular content along with the expelled fluid.

The expressed serum that drains during compression is not waste. It contains fibrinogen, growth factors, and proteins, and some clinicians collect it to moisten graft materials or irrigate the surgical site.

Making Injectable PRF

Not all clinical uses call for a solid membrane. Injectable PRF (i-PRF) is a liquid form designed to be drawn up in a syringe and injected into tissue, mixed with bone graft particles, or used in dermatologic procedures. The preparation is similar in concept but uses a higher centrifugal force and a shorter window of handling.

The recommended protocol for liquid PRF is 700g for eight minutes.¹ At this setting, the blood separates but the upper plasma layer has not yet fully polymerized into a solid fibrin clot. The clinician aspirates this liquid layer with a syringe, working quickly because polymerization continues outside the centrifuge. Once collected, the liquid can be injected directly or mixed with particulate bone graft to create what is often called “sticky bone,” a moldable composite that holds its shape in a surgical defect rather than scattering loosely.

The timing pressure with i-PRF is even tighter than with solid PRF. Because you are trying to capture the product before it solidifies, you have roughly a few minutes after pulling the tubes from the centrifuge to aspirate and use the liquid. Having all syringes and mixing bowls ready before opening the centrifuge lid is essential.

Common Mistakes That Ruin PRF

Several errors come up repeatedly in clinical practice, and most of them are preventable with attention to workflow rather than expensive equipment.

Delayed centrifugation: As described earlier, waiting more than about two minutes between drawing blood and starting the spin is the most frequent cause of poor results. The blood begins clotting in a diffuse, disorganized way, and the centrifuge cannot fix that after the fact.
Wrong tube type: Using tubes that contain anticoagulant (EDTA, citrate, heparin) will prevent clotting entirely. You end up with plasma, not fibrin. PRF requires plain glass or silica-coated tubes with no additives.
Uncalibrated centrifuge: Because g-force depends on rotor radius and RPM together, a protocol listed in RPM from one paper may produce wildly different forces on a different machine. Blindly copying an RPM setting without checking the g-force is a common source of inconsistent results.
Aggressive compression: Pressing the clot too hard or too fast to form a membrane squeezes out the growth factors and cells along with the serum. Gentle, slow compression preserves the fibrin architecture.
Trimming too much of the buffy coat: The red-to-yellow transition zone at the bottom of the clot is where cell concentration peaks. Over-trimming discards the most biologically active portion of the product.

Does It Matter What Medications the Patient Takes?

This is a question clinicians wrestle with, and the evidence is genuinely mixed. A systematic review of 15 studies looking at antiplatelet drugs and NSAIDs found that roughly half of the studies detected no meaningful decrease in growth factor content, while the other half did find reduced growth factor concentrations, particularly when platelets were activated by certain pathways like collagen or arachidonic acid.⁹ Most of this research was done on PRP rather than PRF specifically, and PRF’s natural activation through fibrin polymerization may partly sidestep the pathways that drugs like aspirin inhibit. Still, many practitioners ask patients to avoid NSAIDs for a few days before a PRF procedure as a precaution, even though a definitive answer is not yet available.

Hydration status is another practical variable. Dehydrated patients tend to have more concentrated blood, which can shift the separation dynamics in the centrifuge. There is no rigorous study quantifying the effect on PRF quality, but clinicians commonly advise patients to drink water in the hours before the blood draw, for the same reason phlebotomists recommend it before any venipuncture: it makes the draw easier and the sample more representative.

Advanced Variants and Heat-Treated PRF

The basic PRF protocol has spawned several spin-offs designed for specific clinical problems. One that has gained attention is Alb-PRF, which combines heat-treated albumin with liquid PRF to create a membrane that lasts much longer in the body. Standard PRF membranes, whether L-PRF or the newer horizontal variants, are largely resorbed within about three weeks. The Alb-PRF membrane, by contrast, remained volume-stable throughout a 21-day observation period in animal studies, which represents a significant improvement when the goal is to act as a long-lasting barrier membrane for bone regeneration or as a filler in aesthetic procedures.¹⁰

The preparation involves an extra step: after centrifugation, the cell-poor plasma layer at the top of the tube is collected and heated (typically around 75°C for ten minutes) to denature the albumin into a gel. This gel is then combined with the cell-rich buffy coat zone from the same tube. The result is a hybrid product that has the biological activity of PRF’s growth factors embedded within a more durable scaffold. It requires extra equipment, namely a heating device, and adds time to the workflow, so it is not used routinely. But for cases where membrane longevity is the limiting factor, it fills a gap that standard PRF cannot.

Where PRF Gets Used

Dentistry and oral surgery remain the largest clinical home for PRF. The product is used after tooth extractions to promote socket healing, layered over bone grafts during implant placement, and applied in sinus lift procedures. Sticky bone, the mixture of liquid PRF with particulate bone graft, has shown favorable results in ridge preservation and augmentation, with one retrospective study finding better dimensional outcomes in extraction sockets treated with sticky bone and A-PRF membranes compared to sockets left to heal naturally.¹¹ The rationale is that the fibrin matrix stabilizes the graft particles in place and releases growth factors that promote bone formation while reducing resorption.¹²

Dermatology is a growing area of interest, particularly for injectable PRF. A systematic review comparing PRF and PRP for periorbital rejuvenation found that PRF was associated with improvements in skin texture, wrinkles, and crepiness, while PRP showed stronger evidence specifically for hyperpigmentation. Both had favorable safety profiles with only mild, temporary side effects.¹³ Separately, combining injectable PRF with microneedling produced measurable improvements in skin elasticity and soft wrinkle reduction in clinical testing.¹⁴

Chronic wound management is another active front. Studies on diabetic foot ulcers have shown that L-PRF-treated patients achieve higher healing rates compared to standard care, with lower rates of infection, ulcer recurrence, and amputation. A-PRF has shown comparable healing potential even in complicated cases involving underlying bone infection. Beyond diabetic wounds, PRF has been applied to refractory venous ulcers, pressure ulcers, and other difficult-to-heal wounds with encouraging results.¹⁵

Shelf Life After Preparation

PRF is meant to be used soon after it is made. Because it is an autologous biological product with no preservatives, it degrades over time. Interestingly, one study tracking platelet concentration in PRF clots over time found that storing the clot for 60 minutes actually increased measurable platelet concentration compared to immediate use, suggesting that some continued cell migration into the fibrin matrix occurs after centrifugation. However, storing it much longer risks drying out, bacterial contamination, and breakdown of the fibrin structure. Most clinicians aim to place the PRF within 15 to 30 minutes of preparation and treat anything beyond an hour as suboptimal. Keeping the clot moist with expressed serum and covered on the surgical tray helps extend its usable window, but PRF is fundamentally a prepare-and-use-now product. It cannot be frozen, shipped, or stored for later like some commercial biomaterials.