IS PROCALCITONIN (PCT) AN EFFECTIVE LABORATORY TOOL TO DETECT NOSOCOMIAL SEPSIS (NS) IN NEONATES IN NEONATAL INTENSIVE CARE UNIT (NICU)?
Aim To assess the value of PCT serum levels in detecting NS in NICU neonates.
Methods PCT was determined in the first month of life in 800 non-infected (NI) neonates (219 VLBW). 114 neonates (74 VLBW) developed NS after the third day of life, and PCT was measured at symptoms onset, and 24, 48 hours and 7 days later.
Results The median values (±IQR) of PCT in NI neonates, at day 1, 2, 3 and >7 days of life, were: 0.40 ng/ml (0.21–1.20), 2.38 ng/ml (0.77–8.76), 0.52 ng/ml (0.28–1.37) and 0.49 ng/ml (0.24–1.98) respectively; in NI VLBW infants: 0.35 ng/ml (0.21–0.77), 4.23 ng/ml (0.65–11.23), 0.51 ng/ml (0.35–1.40) and 0.38 ng/ml (0.22–0.80).
In infected neonates the median value (±IQR) of the highest PCT level during NS was 2.84 ng/ml (0.70–21.79) and 2.70 ng/ml (0.64–21.79) in infected VLBW infants (p<0.001 vs NI>7 days). Using ROC curve analysis with the highest PCT value in the first three days of infection, the AUC was 0.79 and, for a cut off value of 2.4 ng/ml, the positive (PPV) and negative (NPV) predictive values were 36.64% and 93.91%, respectively. In VLBW infants the AUC was 0.78, PPV 31.08% and NPV 86.21%.
Conclusions Serum PCT increases in the second day of life and is higher in infected infants. A PCT value below 2.4 ng/ml helps to exclude NS, irrespective of birth-weight and postnatal age. However, the low PPV limits its practical usefulness in the diagnosis of NS.