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

Abstract

Objectives: 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.

Design and methods: 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.

Results: 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%.

Conclusion: 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.