[Procalcitonin a marker in the diagnostic of the newborn with systemic infection]

Laboratory test used in the diagnosis of neonatal sepsis have a low specificity. Recently, procalcitonin has been proposed as a marker to identify the presence of systemic infections. The objective of the study was to evaluate the sensibility and specificity of procalcitonin as a marker of systemic infection in newborn with a suspicion of neonatal sepsis using a blood culture as a gold standard.

21 newborn with a suspicion of neonatal sepsis were included in the study, postnatal age 8.3 +/- 5.2 days in a period from October 2003 to a January 2004. Procalcitonin, were measured at the moment of clinical diagnosis and after 24 and 48 hours and twice blood culture were done.

Seven blood cultures were positive at the moment of diagnosis as well as 21 determinations of procalcitonin, sensibility 85.7%, specificity 21.7%; (OR = 1.63, 95% CI = 0.14-19.4); determinations after 24 hours showed procalcitonin sensibility and specificity of 85.7% and 28.5% (OR = 2.4, 95% CI = 0.22-26.6) and after 48 hours 100% of sensibility and 42.8% of specificity (OR = 1.75, 95% CI = 1.11-2.75]).

Positive procalcitonin has a good sensibility and moderate specificity 48 hours after clinical diagnosis of neonatal sepsis.