1334. Performance of C-Reactive Protein and Procalcitonin in Immunocompromised Children with SIRS

BACKGROUND: Biomarkers (C-reactive protein [CRP], procalcitonin [PCT]) have been used in patients with systemic inflammatory response syndrome (SIRS) to identify those with and without bacterial infection. However, their performance in immunocompromised (IC) children is not well studied. METHODS: Retrospective chart review of episodes of SIRS in IC children <19 years old admitted to the PICU August 2012–June 2016 with: (a) blood culture, PCT, and CRP obtained within 6 hours of SIRS, (b) no recent SIRS episodes (> 30 days), and (c) no positive blood culture in 2 days preceding SIRS. We defined IC as neutropenia (ANC< 500), solid-organ transplant (SOT), hematopoietic cell transplant (HCT), and other (immunosuppressive medications or primary immunodeficiency). To identify a comparator group, we additionally reviewed a previously published cohort of non-IC children with SIRS (Downes, et al, JPIDS 2018), applying the same inclusion criteria. For each episode (first 48 hours after SIRS), we determined the presence of bacterial infection using NHSN definitions and viral infection as symptoms with positive PCR. We compared biomarkers in IC children with and without bacterial infection, and in IC and non-IC children, using Wilcoxon rank-sum tests. RESULTS: We identified 108 SIRS episodes in 94 IC children (neutropenia = 35, SOT = 18, HCT = 22, other = 33) and 278 episodes in 250 non-IC children. Age (P = 0.15) and gender (P = 0.70) were similar among IC and non-IC groups. 41% of episodes in both IC and non-IC children had bacterial infections (P = 0.96). PCT and CRP were significantly higher in IC children with bacterial infection than those without (Figure 1). Biomarkers did not differ significantly among episodes in IC and non-IC children with bacterial infection; however, among episodes without bacterial infection, biomarkers were higher in IC than non-IC children (Table 1). Detection of a viral infection did not affect biomarker values in IC or non-IC children when bacterial infection was absent (Table 2). CONCLUSION: In IC children with SIRS, PCT and CRP were higher when bacterial infection was present. Meanwhile, in the subset of non-bacterial SIRS episodes, biomarkers were higher in IC compared with non-IC children. PCT and CRP may be valuable markers to discriminate bacterial from non-bacterial causes of SIRS in IC children. [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: Kevin J. Downes, MD, Merck: Grant/Research Support, Research Grant; Pfizer: Grant/Research Support.