Evaluation of Plasma Procalcitonin Concentrations in Healthy Foals and Foals Affected by Septic Systemic Inflammatory Response Syndrome

• We evaluated plasma procalcitonin (PCT) concentration in a population of healthy and septic systemic inflammatory response syndrome (SIRS) foals.
• Procalcitonin concentration was greater in septic SIRS foals than in healthy group.
• The positive correlation between PCT concentration and septic SIRS scale suggests that PCT could be a laboratory expression of septic SIRS.
• Procalcitonin could be used as marker for septic SIRS in foals.

The aim of this work was to evaluate procalcitonin (PCT) concentrations in healthy foals and in foals with septic systemic inflammatory response syndrome (SIRS). Plasma PCT concentrations were evaluated in 51 foals, and SIRS scale was calculated. Foals were divided into control group (no septic SIRS criteria met) and septic SIRS group (SIRS score ≥2 plus evidence of sepsis or localized infection). Procalcitonin concentrations were evaluated with a commercial ELISA kit. The data were expressed as mean and standard deviation. A t-test was performed between healthy and septic SIRS groups. A receiver operating characteristic (ROC) curve was carried out. Finally, correlation analysis between PCT concentration and SIRS scale was performed by using Pearson test. The PCT concentrations in control and septic SIRS groups were 30.0 ± 33.1 and 178.9 ± 76.0 pg/mL, respectively. The t-test showed differences between control group and septic SIRS group (P < .0001). A positive linear correlation between PCT concentration and SIRS scale was observed (r = 0.73; r2 = 0.53; P < .0001). The ROC curve was statistically significant (P < .0001), and the best cutoff value to determine septic SIRS was 73.04 pg/mL (87.5% sensitivity, 97.1% specificity, and a likelihood ratio of 30.6). Overall, the results showed an increase in plasma PCT concentrations in septic SIRS foals. A cutoff between control and septic SIRS groups was obtained.