Quantitative determination of procalcitonin is a highly informative test for the diagnosis of infections in newborns

Nosocomial infections and late sepsis are a serious problem for neonatology intensive care units (ICU), being one of the leading causes of morbidity and death rate in patients of these departments. 

According to various analysis, the incidence of sepsis in this category of patients ranges from 15% to 30%. Many cases of infection are caused by coagulase-negative staphylococci. Timely diagnosis of such infections is very difficult due to the lack of specific clinical symptoms and biological markers at an early stage of the disease. As a result, at the slightest suspicion of infection, newborns are prescribed broad-spectrum antibacterial drugs, which in some cases is unjustified. In order to exclude the excessive use of antibiotics in this category of patients, a diagnostic method is needed that has a high prognostic value of a negative result, which will make it possible to exclude the presence of infection in the patient with a high probability.

Procalcitonin (PCT) is known to be a more specific marker of bacterial infection than C-reactive protein (CRP). Therefore, monitoring the dynamics of PCT levels can serve as an additional highly informative method for assessing the likelihood of nosocomial infection and the effectiveness of therapy.

Researchers from Lyon (France), led by A. Jacquot, conducted a prospective analysis in newborns hospitalized in the neonatology ICU with suspected infection based on clinical data. In all children, a rapid quantitative CRP test was also performed in parallel with determining the level of RST. For the period from June 2005 to May 2006 The analysis included 73 newborns with an average gestational age of 28 weeks. (from 26 to 30 weeks) and an average birth weight of 995 g (720-1350 g). The analysis did not include newborns with serious developmental abnormalities, necrotic enterocolitis; patients who required surgical treatment; children who received antibiotics.

In general, the infection was diagnosed in 30 children (41%), of whom 26 (87%) had septicemia, 3 (10%) — meningitis and 1 (3%) — pneumonia. Coagulase-negative staphylococci were the cause of late sepsis in 19 cases (63%), other causative agents of septicemia were Staphylococcus aureus, group B streptococci, Escherichia coli and Pseudomonas aeruginosa. The PCT level was significantly higher in the group of children with confirmed infection — 2.3 ng/ml (range from 1 to 7.8 ng/ml) than in the group of newborns without infection — 0.4 ng/ml (from 0.3 to 1.1 ng/ml, p=0.0084).

As the optimal point of separation of normal and pathological RST values in this category of patients, it is proposed to use an indicator of 0.6 ng/ml, which is characterized by a 100% prognostic value of a negative result and 100% sensitivity; the specificity and prognostic value of a positive result for this separation point were 65% and 67%, respectively.

The results of the analysis indicate that the quantitative test for procalcitonin is highly informative as an additional method for detecting or excluding nosocomial infections in full-term and premature newborns hospitalized in neonatal ICU.

Jacquot A., Labaune J.M., Baum T.P., Putet G., Picaud JC.

Rapid quantitative procalcitonin measurement to diagnose nosocomial infections in newborn infants.

Archives of Disease in Childhood — Fetal and Neonatal Edition 2009; 94: F345-F348.