An Assessment of C-Reactive Protein and Erythrocyte Sedimentation Rate in Ruling Out Acute Infectious Spinal Pathology in Emergency Department Patients: A Retrospective Cohort Study

Summary

This retrospective national-system cohort included 1,963 acute infectious spinal pathology cases and 3,981 controls who presented with spinal pain, had inflammatory markers drawn, and underwent spinal MRI. ESR at or below 20 mm/h or CRP at or below 1.2 mg/dL each corresponded to roughly 90% sensitivity; stricter thresholds increased sensitivity. Using ESR at or below 20 mm/h and CRP at or below 1.0 mg/dL in parallel yielded 98.9% sensitivity and an NPV above 99% in this selected cohort.

Why it matters

Very low CRP and ESR together may reduce the likelihood of discitis, osteomyelitis, spinal epidural abscess, or septic arthritis and can inform MRI decision-making in lower-risk ED patients. The results are not sufficient to use normal inflammatory markers as a stand-alone rule-out when clinical suspicion is substantial.

Main findings

• There were 1,963 AISP cases and 3,981 controls.
• For approximately 90% sensitivity, cut points were ESR <=20 mm/h or CRP <=1.2 mg/dL; for 95% sensitivity, ESR <=12 or CRP <=0.7.
• Parallel ESR <=20 mm/h and CRP <=1.0 mg/dL produced 98.9% sensitivity and NPV >99%.
• No treatment adverse events were applicable because this was a retrospective diagnostic study.

Limitations

Retrospective design with spectrum/selection bias: all included patients had spinal pain, biomarkers, and MRI, and diagnoses were derived from health-system data. Thresholds were derived and evaluated in the same retrospective population and lack prospective management validation.