758 - Impact of the Diagnostic Pursuit of Multisystem Inflammatory Syndrome in Children (MIS-C) on Laboratory Utilization in Hospitalized Pediatric Patients with Common Bacterial Infections

Poster Number: 758
Publication Number: 758.415

Christina M. McKinney, Medical College of Wisconsin, Milwaukee, WI, United States; Amy Pan, Medical College of Wisconsin, Milwaukee, WI, United States; Melodee Liegl, Medical College of Wisconsin, Milwaukee, WI, United States; Glenn Bushee, Children's Hospital of Wisconsin, Mequon, WI, United States; Kelsey Porada, Medical College of Wisconsin, Milwaukee, WI, United States; Erin Preloger, Medical College of Wisconsin, Milwaukee, WI, United States; Patrick J. McCarthy, Medical College of Wisconsin, Milwaukee, WI, United States; Michelle Mitchell, Medical College of Wisconsin, Milwaukee, WI, United States; Kelly Graff, Medical College of Wisconsin, Milwaukee, WI, United States; Sarah Bauer, Medical College of Wisconsin, Milwaukee, WI, United States

Background: Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening disease without specific pathognomonic features or tests that emerged during the COVID pandemic. MIS-C has varied clinical features that may overlap with common bacterial illnesses, possibly resulting in increased use of diagnostics for children with these conditions. Certain labs used in the diagnostic evaluation of MIS-C are not often ordered for common bacterial infections, thus typical values for these conditions are not established.

Objective: To compare laboratory utilization patterns for pediatric patients hospitalized with common bacterial infections with features that may overlap with MIS-C prior to and during the COVID pandemic and determine median and mean values of these studies for each condition.

Design/Methods: A retrospective cohort study was conducted at a tertiary care, free-standing children’s hospital between 2018-2022. The study period was divided into pre-pandemic (Mar. 2018-Feb. 2020) and pandemic (Mar. 2020-Feb. 2022) intervals. Patients > 60 days and < 22 years of age discharged from the hospitalist service with cellulitis, lymphadenitis, pneumonia, or urinary tract infection were included. Patients diagnosed with MIS-C or similar syndrome were excluded. Use of C-reactive protein (CRP), procalcitonin (PCT), ferritin, B-type natriuretic peptide (BNP), D-dimer, troponin, and their initial values during patient encounters were compared and described using descriptive statistics.

Results: 602 encounters met inclusion criteria. Demographics were similar, except for a higher proportion of females in the pandemic group (Table 1). Ferritin, BNP, D-dimer, and troponin were more frequently utilized during the pandemic, without difference in CRP or PCT utilization (Table 2). Mean and median laboratory values were determined and stratified by specific infection (Table 3).

Conclusion(s): Patients hospitalized with otherwise common bacterial infections may incur unnecessary work ups in the COVID-19 era due to pursuit of MIS-C, as demonstrated by a significant increase in ferritin, BNP, troponin, and D-dimer utilization in the pandemic interval. Utilization of CRP and PCT was unchanged, suggesting their routine use in bacterial infections at baseline. Attention to specific MIS-C epidemiologic factors may help limit laboratory overuse and mitigate the potential for increased costs. Laboratory values in common bacterial conditions are reported, with unclear utility in differentiation from MIS-C. Limitations include small sample size, underrepresentation of some bacterial infections, and retrospective design.