One of the most challenging diagnoses to make is that of a spinal epidural abscess (SEA), especially if you work in an Emergency Department which cares for many IV drug users and HIV patients. There’s never before been a published diagnostic guideline or algorithm which helps you with risk-stratification.
In the Journal of Neurosurgical Spine, a diagnostic guideline was prospectively evaluated on a small population (n=31) as compared to historical controls (n=55). They found that an ESR test had a sensitivity of 100% if a patient had at least 1 risk factor for SEA. A CRP test was much less helpful.