Harvesting PRP for hair treatments is done with the help of a collection tube. A Los Angeles practitioner will draw a blood sample from you, similar to that amount that is required to conduct a lab test. This tube will then be placed in a centrifuge that will separate the platelets in your blood. These platelets will then be treated and concentrated in plasma. Once they are activated in this manner, they are able to produce and signal to proteins that facilitate cell growth and wound repair.