Can Procalcitonin Be an Accurate Diagnostic Marker for the Classification of Diabetic Foot Ulcers?

The differentiation of infected diabetic foot ulcers (IDFU) from non infected diabetic foot ulcers (NIDFU) is a challenging issue for clinicians. Recently, procalcitonin (PCT) was introduced as a remarkable inflammatory marker. We aimed to evaluate the accuracy of PCT in comparison to other inflammatory markers for distinguishing IDFU from NIDFU. We evaluated PCT serum level as a marker of bacterial infection in patients with diabetic foot ulcers. Sixty patients with diabetic foot ulcers were consecutively enrolled in the study. A total of 30 patients were clinically identified as IDFU by an expert clinician, taking as criteria for purulent discharges or at least two of manifestations of inflammation including warmth, redness, swelling and pain. Procalcitonin, white blood cells (WBCs), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), were found significantly higher in the IDFU group compared to the NIDFU group. The best cut-off value, sensitivity and specificity were 40.5 mm/h, 90% and 94% for ESR, 7.1 mg/dL, 80% and 74% for CRP, 0.21, 70% and 74% for PCT, and 7.7×109/L, 66% and 67% for WBCs, respectively. The area under the receiver operating characteristic curve for ESR was the greatest (0.967; P < 0.001), followed by CRP (0.871; P < 0.001), PCT (0.729; P < 0.001), and finally WBCs (0.721; P = 0.001). These results suggest that PCT can be a diagnostic marker in combination with other markers like ESR and CRP to distinguish infected from non-infected foot ulcers, when clinical manifestations are un specific. Additional research is needed before the routine usage of PCT to better define the role of PCT in IDFU.