Fig. 3. Platelet activation rates. (A) Fresh platelet-rich plasma (PRP) immediately after preparation (pre-activation). (B) Activated fresh PRP. (C) Activated freeze-dried PRP 8 weeks after preparation. The percentages of activated platelets in the freeze-dried samples were similar to those in the fresh PRP, even after 8 weeks. Horizontal axis, anti-CD41a antibody (platelet marker); vertical axis, anti-CD62P antibody (activated platelet marker).