Diagnostic usefulness of serum procalcitonin in patients with bacterial sepsis

The Sequential Organ Failure Assessment (SOFA) score is used for the diagnosis of sepsis and involves clinical and laboratory parameters that may not be readily and/or timely available in most resource-poor settings. Procalcitonin (PCT) has its level changed in response to bacterial sepsis and its measurement costs only a fraction of the total cost of investigations required to calculate SOFA score. This study aims to determine the diagnostic usefulness of PCT in bacterial sepsis.

Ninety-nine participants were studied, divided into three groups: apparently healthy volunteers, those with bacterial infection without sepsis (SOFA score <2), and patients with bacterial sepsis (positive culture and SOFA ≥2). PCT level of each participant was measured and median group levels compared. Pearson's correlation was used to determine the correlation between serum PCT levels and SOFA scores in the sepsis group using a significance level of 5 percent (P < 0.05). Diagnostic usefulness of PCT was assessed using receiver operating characteristic (ROC).

Positive correlation was found between serum PCT levels and SOFA scores among patients with sepsis r = 0.42, P = 0.016. At a concentration of ≥4.25 ng/ml, serum PCT as a surrogate for SOFA score had a sensitivity and specificity of 57.60% and 84.80%, respectively, for indicating sepsis. The area under the ROC curve (AUC) was 0.74 (95% CI {0.62 to 0.86}, P = 0.001).

Serum PCT concentration was significantly higher in bacterial sepsis compared to bacterial infection without sepsis and healthy state. PCT concentration demonstrated positive correlation with SOFA score in bacterial sepsis and can be used as surrogate for sepsis screening/monitoring in resource-poor settings.