This is a double-blinded study where the injecting physicians and the patients will not know which arm they are randomized to. Each participant will be followed up for 6 months following the injection, and will have in office visits at the injection and approximately 2 weeks post injection. They will be called at month 1, 3, and 6 post injection to assess for any adverse events and number of physical therapy hours or changes in medication. At time of injection, 2 weeks post, and 1, 3 and 6 months after they will be asked to answer some questionnaires on pain and function.

Sacroiliac joint (SIJ) pain is a common and significant source of chronic low back pain. It has been broadly defined as pain located in the area of the SIJ that can be elicited by various pain provocation tests and relieved after infiltration of the joint with local anesthetic.

Essentially, a patients own blood is collected and spun at varying speeds until it separates into 3 layers, one of which is the platelet-rich plasma. Platelet-rich plasma (PRP) injections are commonly used in various conditions including chronic tendinopathy, soft tissue injuries, and ligamentous injuries. More recently, there has been a greater interest in examining the efficacy of PRP as a treatment for musculoskeletal conditions affecting joints, such as osteoarthritis (OA). To the investigators' knowledge, there are currently no reported studies evaluating the efficacy of PRP for SIJ pain. Given the previously discussed application and evidence behind the use of PRP in the knee and hip joints, the investigators propose that PRP can also provide a similar solution for treating SIJ pain.

Inclusion Criteria:

• Aged 18 years and older
• Sacroiliac/Lower back pain
• Positive block
• Eligible for steroid injection
• Positive physical manual assessments

Exclusion Criteria:

• Steroid allergy