Comparison of a rapid bed-side test with a central laboratory analysis for C-reactive protein in newborn infants with suspicion of sepsis

Abstract

Background: Neonatal sepsis is one of the leading causes of neonatal morbidity and mortality in the newborn period. The purpose of this study was to compare a rapid bed-side test against central laboratory analysis for CRP in newborn infants with suspicion of sepsis.

Methods: We included 23 newborn infants with suspected or proven sepsis (group 1). Age and gender matched 40 infants without sepsis were assigned as controls (group 2). A total of 116 blood samples (58 samples from each group) were drawn from the peripheral vein for C-reactive protein (CRP) measurements. For the NycoCard CRP tests, 5 microL of whole blood and the same amount of serum was used to determine the CRP value (wCRP-N and sCRP-N). As the reference CRP test, serum concentrations of CRP (CRP-Lab) were simultaneously measured by immunonephelometric method requiring 1 mL of serum sample. CRP values > or = 10 mg/L were considered positive for all three tests.

Results: It was found that the median values of wCRP-N (18.9 mg/L), sCRP-N (25 mg/L), and CRP-Lab (22.2 mg/L) of group 1 were higher than group 2 (wCRP-N: 1.1 mg/L, sCRP-N: 5 mg/L, and CRP-Lab: 2.9 mg/L) (p < 0.001). Nycocard-CRP were positively correlated with CRP-Lab. With considering CRP-Lab positive at > 10 mg/L, both CRP-NycoCard tests have high sensitivity and specificity, although sCRP-N has slightly higher predictive values. Passing-Bablok regression and Bland-Altman analysis showed that NycoCard tests have no statistically significant systematic proportional bias.

Conclusions: Nycocard-CRP tests have high predictive values, require a very small amount of blood, and results can be obtained quickly. Determinations of CRP concentrations by NycoCard-CRP test seems to be helpful in distinguishing septic and aseptic newborns.