Erythrocyte Sedimentation Rate, C-Reactive Protein and Procalcitonin in Infections of the Spine and Infections in Spinal Cord Injury Patients

The most widely used inflammatory markers are erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and procalcitonin (PCT). A review of the literature was done on their application in spinal infections and spinal cord injury (SCI) patients. ESR, CRP and PCT as markers of infection have their uses in various but specific medical conditions. SCI patients are unique because they are in a chronic state of inflammation. In these patients, CRP >50 mg/L may support the diagnosis of true UTI. In those with chronic infections of the spine/vertebrae, an ESR of >20-30 mm/h appears superior to an elevated CRP for diagnosis, although it is still preferred to do both tests. Serum PCT of >0.4 ng/mL was reported to be highly specific in diagnosing acute osteomyelitis, but evidence was very limited. No study on PCT for chronic osteomyelitis was found. In post-spine surgery patients, CRP is more useful than ESR, while PCT is superior to CRP in detection of post-operative infections because the former does not rise too high, even after major neurosurgery. PCT of >0.5 ng/mL is reasonable evidence to start antibiotics and further investigation, while levels <0.1 ng/mL suggest absence of infection. CRP is inferior to PCT in diagnosing post-spine surgery infections, but it may be used when cost is an issue or when PCT is unavailable. This is the first literature review of the most widely used biomarkers, including PCT, and their application in the diagnosis of infections of the spine and infections in SCI patients.