Procalcitonin as a Biomarker for Predicting Amputation Level in Lower Extremity Infections

Inflammatory markers are essential tools in the decision-making process for lower extremity infections. When coupled with objective findings, clinicians can more accurately diagnose and treat these entities. Typically, markers such as the white blood cell count, erythrocyte sedimentation rate, and C-reactive protein are used to initially assess these patients or monitor the progression of medical or surgical therapy. Procalcitonin is a newer inflammatory marker that is specific for an infectious process. Originally, procalcitonin was used to monitor antibiotic therapy and sepsis for patients in the intensive care setting, but it has now been expanded to other facets of medicine. The utility of procalcitonin has been described for diagnosing infection or osteomyelitis in diabetic foot ulcers. However, limited research has compared inflammatory marker levels and the level of amputation. A retrospective inpatient medical record review was performed of 156 consecutive patient occurrences during 25 months in which surgical intervention was required for a lower extremity infection and an initial procalcitonin level had been obtained. This initial procalcitonin value was then compared with the level of amputation at the final surgical intervention. A highly statistically significant difference was found when comparing those who underwent a below-the-knee or above-the-knee amputation (median procalcitonin 1.72 ng/mL) and those who did not (median procalcitonin 0.105 ng/mL; p < .001). Therefore, patients with higher initial procalcitonin values were more likely to undergo below-the-knee or above-the-knee amputation or require aggressive surgical intervention. Thus, the procalcitonin level can provide valuable initial information to the clinician.