Procalcitonin measurement for detection of serious bacterial infection in febrile children: Comparison between two automated immunoassays

Abstract

To assess the concordance of procalcitonin values at 3 cut-off ranges in a cohort of pediatric samples presenting with fever without source, using two different automated immunoassays. 65 frozen samples from children presenting with fever without source were thawed, tested on both Kryptor and VIDAS systems, and compared using a regression analysis, a Bland-Altman difference plot, and analysis of concordance at the clinically relevant cut-off points. Kryptor and VIDAS PCT results correlated remarkably well (r=0.952), with no significant difference in the frequency distribution over the 3 cut-off ranges (p=0.1384). The strength of the agreement was good (κ=0.759) with an overall concordance of 84.6%. Correlation and concordance of PCT values measured by both systems were good. This finding allows clinical implementation of both techniques with the same nominal PCT cut-off values for detection of serious bacterial infection in children presenting with fever without source.