Rapid quantitative procalcitonin measurement to diagnose nosocomial infections in newborn infants

Background and objective: Serum procalcitonin (PCT) monitoring may help clinicians to manage nosocomial infections in neonates. This study investigated the diagnostic value of a new, rapid method to measure PCT and sought to determine the best cut-off value. Methods: This monocentric, prospective study included all newborn infants with clinical suspicion of infection in a neonatal intensive care unit. Rapid, automated PCT measurements were performed on blood samples obtained for C-reactive protein (CRP) measurement. Negative and positive predictive values, sensitivity and specificity were calculated. Logistic regression analysis determined the best cut-off value to obtain a negative predictive value of PCT that was at least 15% above that of CRP. Results: Between June 2005 and May 2006, 73 newborn infants with a median (Q25-Q75) gestational age of 28 (26-30) weeks and a birth weight of 995 (7201350) g were included. Thirty (41%) were infected. The best PCT cut-off value was 0.6 ng/ml, which provided a negative predictive value of 100%. The sensitivity, specificity and positive predictive value were 100%, 65%, and 67%, respectively, for PCT at the 0.6 ng/ml cut-off value. Conclusion: Rapid measurement of PCT could help to rule out nosocomial infection in newborn infants hospitalised in intensive care units.