Diagnostic Use of C-Reactive Protein (CRP) in Assessment of Neonatal Sepsis

Objectives

After completing this article, readers should be able to:

1. Explain factors that render neonatal blood culture results less reliable when neonatal sepsis is suspected.

2. Describe the factors that confound results of C-reactive protein (CRP) measurement.

3. Explain the relevance of two negative CRP results within 48 hours in a stable patient when bacterial sepsis is being considered.

4. Delineate promising new markers for neonatal sepsis.

Introduction

A 2005 National Library of Medicine PubMed literature search on C-reactive protein (CRP) limited to human neonates and English language identified about 160 citations. Only two of these articles referenced a randomized, controlled clinical trial. Despite the large body of literature on CRP, there is no established standard of practice for the use of CRP in assessment of neonatal sepsis.

The Pursuit of a Diagnostic Sepsis Marker

Data from the National Institute of Child Health and Human Development Neonatal Research Network indicate that the rate of early-onset sepsis is 1.5% in very low-birthweight (VLBW) infants; almost half (46%) of neonates born at less than 25 weeks’ gestation develop late-onset sepsis. Current recommendations for the treatment of neonates who have possible or proven sepsis are intravenous antibiotics for 48 to 72 hours for stable infants who have negative blood culture results and for 7 to 14 days for blood culture-positive or clinically probable infection. It has been estimated that this approach results in treatment of up to 30 uninfected infants for every 1 infected infant. In addition, since the implementation of the Centers for Disease Control and Prevention guidelines for maternal intrapartum antibiotic prophylaxis, blood culture results as the “gold standard” are often unreliable. Identification of a diagnostic sepsis marker that has high negative predictive value may reduce the short- and long-term adverse effects of antibiotics and reduce health care costs and length of hospital stay.

What is CRP?

CRP was described initially in 1930 by Tillet and …