Inclusion Criteria:  patients with known or suspected spinal infections associated with spinal orthopedic implant(s); patients over 18 years of age and younger than 85; patients undergoing spinal revision surgery.  Exclusion Criteria:  Diagnosed as immuno-compromised or immuno-suppressed based on medication use; On-going or previously diagnosed musculoskeletal infections associated non-spine hardware (e.g., prosthetic hip, prosthetic knee, prosthetic shoulder); Current diabetic foot ulcer/infection; Patients undergoing cancer treatment (including radiation and chemotherapies); Pregnancy; Absence of a spleen; Over the age of 85 or under the age of 18. Weigh less than 110 pounds, or for which it would otherwise be unsafe for them to undergo a blood draw.