Objective: 1) Survey procalcitonin concentrations in infant infections. 2) finding the relationship between the concentration of procalcitonin with plasma CRP levels. Method: Prospective longitudinal study describes, in 20 children diagnosed with neonatal sepsis. Procalcitonin concentrations were quantified according to the principle of Electrochemiluminescence immunoassay (ECLIA). Result: 1) The concentration of PCT increased at a time when the patient hospitalized was 2.55 ng/ml
after 12 hours was 2.66 ng/ml
after 24 hours was 3.32 ng/ml, after 72 hours and reached the lowest decreasing 0.09 ng/mI. 2) The PCT 0.5nglmL, diagnosis of neonatal sepsis was 100 percent correct
with CRP 2: 10 mg/L, diagnosis of infection is 20 percent correct only. Conclusion: 1). Plasma procalcitonin concentrations increased during the period of neonatal sepsis and return gradually return to normal levels after 72 hours in hospital. 2) The increasing concentration of procalcitonin in neonatal sepsis is more meaningful than CRP.