Diagnostic and prognostic role of procalcitonin (PCT) and MR-pro-Adrenomedullin (MR-proADM) in bacterial infections

Rapid diagnosis of bacterial infections is crucial for adequate antibiotic treatment. Serum molecules such as Procalcitonin (PCT) have been used as biomarkers of infection. Recently, the mid-regional pro-Adrenomedullin (MR-proADM) has been evaluated in combination with PCT for sepsis diagnosis. The diagnostic role of PCT and MR-proADM both in sepsis and in localized infections together with their contribution to effective antibiotic therapy has been evaluated. One hundred and eighty-two patients with bacterial infection has been enrolled: PCT and MR-proADM were measured at admission (T=0), at 12-24h (T=1) and in the third or fifth day of antibiotic therapy (T=3-5). ROC curve (receiver operating characteristic) and post-test probability were calculated. MR-proADM increased with the severity of the infection. PCT resulted significantly higher in sepsis than localized infection. After antibiotic therapy, PCT significantly decreased in localized respiratory infections and in sepsis, while MR-proADM decreased significantly after antibiotic therapy only in patients with severe sepsis/septic shock. The threshold values of PCT and MR-proADM were >0.1ng/mL and >0.8nmol/L, respectively. The combined use of PCT and MR-proADM increased the post-test probability of the diagnosis of bacterial infections compared to PCT alone. In conclusion, PCT and MR-proADM combination improves the diagnosis of bacterial infection and contribute to prognosis and antibiotic therapy effectiveness.