The role of procalcitonin as a predictor of nosocomial sepsis in preterm infants

Aim: To assess the role of procalcitonin in detecting nosocomial sepsis in preterm infants, after the onset of clinical symptoms. Subjects: 100 preterm infants, 24-36 wk of gestation, were followed from the age of 3 d until discharge. Procalcitonin and C-reactive protein (CRP) levels were measured within 3 d of sepsis workup events. Results: 141 blood samples were drawn from 36 infants during 85 episodes of sepsis workup performed between 4 and 66 d of life. Of these episodes, 51 (60%) were not a result of documented sepsis and thereby served as the negative comparison group. Median procalcitonin levels were higher in the septic group compared with the non-septic group at the time of the sepsis workup (2.7 vs 0.5 ng/ml, p=0.003), at 1-24 h after the sepsis workup (4.6 vs 0.6 ng/ml, p=0.003), and at 25-48 h (6.9 vs 2.0 ng/ml, p=0.016). Using high cutoff levels, both procalcitonin (2.3 ng/ml) and CRP (30 mg/l) had high specificity and positive predictive value (97%, 91% and 96%, 87%, respectively) but low sensitivity (48% and 41%, respectively) to detect sepsis. Areas under the ROC curve for procalcitonin and CRP were 0.74 and 0.73, respectively. Conclusion: Procalcitonin > 2.3 ng/ml or CRP > 30 mg/l indicates a high likelihood for neonatal sepsis, and antibiotic therapy should be continued even in the presence of sterile cultures.