Inclusion Criteria- Septic Cases and Inflamed, Non-Septic Comparators:

• Synovial fluid is obtained to assess for infection or inflammatory/rheumatologic disease (all medium and large joints will be included: hip, knee, ankle, shoulder, subtalar, elbow, and wrist joints)
• Patients with recent antibiotic exposure are eligible to participate but will be analyzed separately

Inclusion Criteria- Normative Controls:

• Patients undergoing a procedure unrelated to infection (the procedure may be arthroscopy, or an open or percutaneous bony or soft tissue procedure)

Exclusion Criteria- All Participants:

• Family declines to participate/consent
• Patients with a major joint trauma (such as a documented ligament tear or fracture) within the past 8 weeks are not eligible to have that joint aspirated, but could have another joint aspirated

Exclusion Criteria- Normative Controls:

• A history of recent infection (within the past 3 months)
• Received antibiotics in the past 7 days