Platelets in platelet-rich plasma (PRP) prepared using the Clinaseal Centrifuge method contain intact growth factors. Western blotting was used to qualitatively assess whether platelets in PRP prepared using the methods described contain platelet-derived growth factor (PDGF-BB) or transforming growth factor-β1 (TGFβ1). Lane 1: molecular weight markers that flank the growth factor protein bands of interest. Lane 2: purified recombinant human growth factors that serve as positive controls. Lane 3: lysate from 5 to 7 × 10⁶ partially purified platelets contained within the PRP. Note the presence of bands in Lane 3 that correspond in migration and immunoreactivity to the standard growth factors in Lane 2. Also note that the bands in Lanes 2 and 3 migrate to the known molecular weight range for each growth factor monomer (PDGF-BB = 15 kD, TGFβ1 = 12.5 kD, nerve growth factor = 14 kD).