Work directed by Dr. Robert Marx in the 1990s led to the popular working name ‘platelet rich plasma’ (PRP). The goal of PRP was to collect the largest and highest concentrations of platelets/growth factors to be later utilized for regenerative purposes. The PRP protocol required extensive centrifugation time (typically over 30 minutes). During this process, the use of anticoagulants (namely bovine thrombin or calcium chloride) was absolutely necessary in order to prevent clotting owing to the lengthy centrifugation times. The final composition of PRP contained over 95% platelets, known cells responsible for the active secretion of growth factors involved in wound healing.

Two reported drawbacks of PRP have since been reported in the literature. First, centrifugation times were deemed long (>30 minutes) and not practical for a variety of surgical procedures that may routinely be performed in many clinical practices. Furthermore, it has since been revealed that clotting in general, is a necessary component of normal physiological wound healing. This limitation of using anti-coagulants prevented optimal and led to the development of platelet rich fibrin

Very recently, a series of studies has shown that horizontal centrifugation of PRF is capable of producing significantly greater concentrations of platelets and leukocytes when compared to the currently available fixed-angle centrifugation devices most commonly utilized to produce L-PRF or A-PRF.

It was reported that one of the major disadvantages of fixed-angle centrifugation is that during the spin cycles, cells are typically driven along the back wall of centrifugation tubes at high g-forces. This exposes cells to high compressive forces against the back wall and must thereafter travel either up or down the inclined centrifugation tube based on cell density differences. Since red blood cells are larger and heavier than platelets and leukocytes, they typically travel downwards, whereas lighter platelets travel towards the top of the tube where PRF is collected. Noteworthy however, it was shown that on a fixed angle centrifuge, cells accumulate at the back walls of centrifugation tubes and the larger red blood cells entrap the smaller platelets/leukocytes below them and drag them into the red corpuscle layer. By utilizing a fixed-angle centrifuge, it is not possible to maximize platelet and leukocyte numbers as a result of fixed-angle centrifugation.

By utilizing a horizontal swing-out bucket centrifugation system, it becomes possible to fully separate cells and blood layers based on their density without necessitating cells to accumulate/damage on the back walls of centrifugation tubes. By utilizing horizontal centrifugation, it therefore becomes possible to isolate a higher number and concentration of platelets, leukocytes and monocytes when compared to either the L-PRF or A-PRF protocols.