Comparative Evaluation of the Diagnostic Value of Procalcitonin and hsCRP for the Presence of Mild-to-Moderate Diabetic Foot Infections

The aim of this study is to compare the efficacy of procalcitonin (PCT) and high-sensitive C-reactive protein (hsCRP) as diagnostic biomarkers in patients with diabetes and mild-to-moderate diabetic foot infections. A total of 119 patients (102 with type 2 diabetes and 17 with type 1 diabetes), of mean age 60.29 +/- 10.05 years, divided into 3 groups-diabetic foot ulcer (DFU) with active infection (IDFU group, n = 41), DFU without clinical signs of infection (non-IDFU group, n = 35), and a control group with diabetes without DFU (n = 43). Infection severity was graded according to the International Working Group on the Diabetic Foot guideline-non-IDFU group as Grade 1, IDFU group as Grade 2 (n = 22), and Grade 3 (n = 19). Serum hsCRP was assessed by the immunoturbidimetric method and PCT by the enzyme chemiluminescence immunoassay (ECLIA) method. Levels of white blood cells (WBC) were assessed using the Medonic hematology analyzer and erythrocyte sedimentation rate (ESR) by the Westergren method. Serum hsCRP, WBC count, and ESR were significantly higher in the IDFU group as compared to non-IDFU and control groups, whereas PCT levels did not differ between the groups. hsCRP presented with higher sensitivity (80%), specificity (79%), area under the curve (AUC) 0.856, in comparison to PCT (sensitivity 63%, specificity 62%, AUC 0.617) for the presence of IDFU, as well as in the Grade 3 subgroup (84% sensitivity and specificity, AUC 0.911). The combined model of both markers did not present with better accuracy than using hsCRP alone. In conclusion, hsCRP appears to be a better diagnostic biomarker than PCT in the diagnosis of moderate foot ulcer infection. Both markers fail to distinguish mild infection.