Comparison of procalcitonin with interleukin 8, C-reactive protein and differential white blood cell count for the early diagnosis of bacterial infections in newborn infants.
OBJECTIVE
To evaluate procalcitonin (PCT) as a test for early diagnosis of bacterial infections (BI) in newborn infants and to compare the results of PCT with those of interleukin 8 (IL-8), C-reactive protein (CRP) and differential white blood cell count.


METHODS
PCT was prospectively measured along with IL-8, CRP and differential white blood cell counts and blood cultures in 197 newborn infants at the first suspicion of bacterial infection. PCT, IL-8, CRP and differential white blood cell counts were analyzed for sensitivity, specificity and positive and negative predictive values after receiver operating characteristic curve analysis for best thresholds. The kinetics of PCT was determined in infants with and without BI.


RESULTS
Forty-six infants were diagnosed clinically as having BI, of whom 9 had BI with positive blood cultures. At a cutoff value of 0.50 microg/l, PCT detected combined culture-proved and clinical BI with a sensitivity of 57% (95% confidence interval, 41%, 71%) and a specificity of 66% (95% confidence interval, 57%, 74%). The combination of IL-8 > or =70 ng/l and/or CRP >10 mg/l achieved a sensitivity of 91% (95% confidence interval, 79%, 98%) and a specificity of 73% (95% confidence interval, 64%, 81%). PCT values of infected and not infected infants tended to rise for 24 h after initial evaluation and then decreased.


CONCLUSIONS
The combination of IL-8 and CRP is more reliable than PCT as a test for early diagnosis of BI in newborn infants.
Franz
A R
AR
Department of Pediatrics, University of Ulm, Germany. axel franz@medizin uni-ulm.de.
Kron
M
M
Pohlandt
F
F
Steinbach
G
G
D001424:Bacterial Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D002097:C-Reactive Protein / Q000032:analysis*; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016209:Interleukin-8 / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D011446:Prospective Studies; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity
C000606589:CALCA protein, human; D016209:Interleukin-8; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide