Serum procalcitonin as an early marker of neonatal sepsis.

Background: It has recently been suggested that procalcitonin (PCT) is of value in the diagnosis of neonatal sepsis, with varying results. This study was to evaluate the role of PCT as a single early marker of neonatal sepsis.

Methods: Neonatal Unit, Johannesburg Hospital, and Microbiology Laboratory, National Health Laboratory Service (NHLS), South Africa. Methods: Neonates undergoing evaluation for sepsis between April and August 2002 were eligible for inclusion. Patients were categorised into 'no infection', 'possible infection' and 'definite infection' on the basis of C-reactive protein (CRP), white cell count (WCC), platelet count and blood culture results. PCT was correlated with infection categories.

Results: One hundred and eighty-three neonates were enrolled. One hundred and eighteen had no infection, 52 possible infection and 13 definite infection. PCT differed significantly among infection categories (p < 0.0001) and correlated significantly with CRP at presentation (correlation coefficient 0.404, p < 0.001) and CRP at 24 hours (correlation coefficient 0.343, p < 0.001). PCT predicted 89.5% of definite infection. Receiver operating characteristic (ROC) analysis for PCT to predict definite infection showed odds ratio (OR) 1.145 (95% confidence interval (CI): 1.05-1.25) with an area under the curve of 0.778. PCT had a negative predictive value of 0.95 (95% CI: 0.915-0.988) for definite infection.

Conclusions: Although PCT was significantly related to the category of infection, it is not sufficiently reliable to be the sole marker of neonatal sepsis. PCT would be useful as part of a full sepsis evaluation, but is relatively expensive. A negative PCT on presentation may rule out sepsis, but this needs to be evaluated further.