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Comparision of Procalcitonin with C-Reactive protein in the diagnosis of late onset sepsis in newborn.

Three Part Question

In [neonates] [Procalcitonin is a better marker of infection] as comapared to C reactive protein in [late onset sepsis]

Clinical Scenario

In a tertiary care neonatal unit a 30 weeks preterm was admitted from delivery suite. There was no any maternal risk factor for sepsis. The neonate remained stable in the first week of life. A percutaneous long line was sited on day 4 and parenteral nutrition was started. On day 8 he started having frequent desaturations & bradycardias, which later needed ventilation. In the view of deterioration he had partial septic screen, the FBC, CRP and Blood culture. The initial & repeated CRP remained negative. He had bedside Procalcitonin checked 24 hours after his illness started which came back strongly positive. The Blood culture grew gram positive cocci. The PCT responded to antibiotic therapy. We wonder if PCT is a better marker of neonatal sepsis than C-reactive protein.

Search Strategy

Primary sources: searched Pubmed
Secondary source: Cochrane: no relevant results
Search terms: "Procalcitonin(PCT)", "C reactive protein(CRP)" and "late Neonatal sepsis".
LIMIT to humans ,English Language, new born 0-1 month of age. Search outcome

Search Outcome

5 papers were found out of which only one was relevant

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Ramesh Vazzalwar et al
Cases: 51, Controls:16 <37 week gestation, <1500 gm, >7 days old, no antibiotics in last 48 hours with clinical and laboratory suspicious of sepsis, apart form FBC, CRP, PCT appropriate cultures were also taken. Divided in 3 groups Group I: Confirmed, Probably or possibly infected Group II: suspected but Not infected Group III: controls ( Healthy, VLBW)Prospective, observationalSerial PCT & CRPThe mean PCT & CRP were significatly higher in Group I. three different of sensitivity, specificity, positive & negative predictive values were calculated. The sensitivity of PCT is higher as compared to CRP in group 1. The PCT falls rapidly with treatment then CRPStudy limited to VLBW babies, no power calulations done, probably under powered for the question. Controls were significantly greater gestation age and weight.


The signs and symptoms of neonatal sepsis are very non-specific and and some times may be because of non infectious causes. Traditionally we use CRP as an early marker of neonatal sepsis but we know from our experience that despite having very strong clinical suspicion some babies never show any CRP response further more CRP cannot differentiate between bacterial and other infections. Procalcitonin is the precursor of calcitonin and has no hormonal activity. It has been shown in various studies that the levels of PCT rises with bacterial infections. Furthermore, the finding that PCT is released into the circulation within 3 h after endotoxin injection, plateaus at 6 h, and remains elevated for 24 h, makes PCT a promising new agent for early and sensitive identification of severe infection both in adults and children with promising results. In contrast to CRP , PCT levels stabilized at 48 hours of treatment and decrease back to normal value within 2-3 days. For this reason PCT may be useful as a prognostic marker. CRP has long half life and take up to 5-7 days to normalize

Clinical Bottom Line

PCT be useful in the early diagnosis of late onset neonatal sepsis. Further large scale studies are needed to confirm that it is a better marker than CRP.


  1. Vazzalwar R, Pina-Rodrigues E, Puppala BL, Angst DB, Schweig L. Procalcitonin as a screening test for late-onset sepsis in preterm very low birth weight infants J Perinatol. 2005 Jun 25(6):397-402