Associations between procalcitonin and markers of bacterial sepsis

Bacterial sepsis with no bacterial isolates can be a difficult clinical conundrum, where other markers like C-reactive protein (CRP), white cell count (WCC), and neutrophilia are helpful to arrive at a diagnosis. Procalcitonin (PCT) has been shown to be a useful biomarker in bacterial sepsis. The aim of the study was to look at the association of PCT with bacterial cultures and compare this to currently used markers of bacterial sepsis.

WCC, neutrophil count, and CRP with PCT were compared in patients with a positive bacterial culture from blood/body fluid. The specificity and sensitivity of PCT were compared with those of CRP.

Of the 99 paired samples obtained, 25 cultures were positive for bacteria. There was a significant difference in CRP (P=0.04) and PCT (P<0.001) levels between culture-positive and culture-negative samples. PCT had a better sensitivity and specificity than CRP (84% and 64.9% vs. 69.6% and 52.9%, respectively), with a combined specificity (CRP and PCT) of 83.5%.

PCT has a better association with bacterial sepsis and is superior to currently available biomarkers in the clinical setting. The rapid pharmacodynamics of PCT can serve as an early predictor of the diagnosis of bacterial sepsis while awaiting the bacterial culture results avoiding undue delay in the institution of antibiotics, hence, potentially improving the prognosis of patients with bacterial sepsis.