Usefulness of procalcitonin in elderly patients with bacterial infection.

Background: The role of PCT (procalcitonin) in elderly patients with bacterial infection has not fully been investigated. In previous studies, the role of PCT in diagnosing bacterial infection has mainly been studied in patients with severe infections. This study was to access a diagnostic value of PCT in elderly patients with local infection. Methods: A total of 259 elderly patients were enrolled in this study. Serum concentration of PCT and whole blood concentration of CRP was measured by immunofluorescence assay. Results: The concentration of PCT was significantly higher in patients with infection than those without. In predicting bacterial infection, with a PCT cutoff value of 0.055 ng/mL, the specificity and sensitivity were 92.4% and 63.6%, respectively, while the specificity and sensitivity was 80.0% and 81.3% with a CRP cutoff value of 10.96 mg/L. The areas under the receiver operating characteristic curves (ROC-AUCs) of PCT and CRP were 0.792 and 0.858, respectively (p < 0.05). Conclusions: PCT may not be a better predictor than CRP for diagnosing bacterial infection in elderly patients, but its high specificity is helpful to rule in a bacterial infection.