Use of procalcitonin as a biomarker for sepsis in moderate to major paediatric burns

Introduction Accurate and early detection of sepsis poses a significant challenge in burn populations. Our objective was to assess whether procalcitonin is a marker of blood culture positive sepsis in moderate to severe paediatric burns. Methods We analysed procalcitonin levels in 27 children admitted with burns of 15-65% total body surface area. Procalcitonin was measured at admission (baseline), 24 and 48 h post-admission and during periods of suspected sepsis (diagnosed against pre-defined criteria). Patients were categorised into controls with no episodes of suspected sepsis (n = 10) and those with episodes of suspected sepsis (n = 17). The latter were split into two groups based on blood culture results: culture positive (bacteraemia) and culture negative patients. Results Baseline procalcitonin levels increased with burn size (odds ratio (95% confidence interval): 1.15 (1.02-1.29)). Suspected sepsis patients had larger burns than controls (median 31 vs. 20%; p = 0.003). Only 5/23 suspected sepsis episodes were blood culture positive. Procalcitonin levels were similar in culture positive and culture negative patients (p = 0.43). Sensitivity for predicting positive blood culture was 100% (95% confidence interval: 47.8-100.0%) but specificity was only 22.2% (95% confidence interval: 6.4-47.6%). Area under the curve was poor at 0.62 (95% confidence interval: 0.33-0.90). There was no significant change in procalcitonin levels from baseline to septic episode in either group (positive: p = 0.35; negative: p = 0.95). Conclusion We conclude that evidence for the use of procalcitonin to diagnose bacteraemia in this population is poor, with burn size playing a significant role implying a correlation with systemic inflammation rather than sepsis.