To compare clinical and laboratory features of children with Multisystem Inflammatory Syndrome in Children (MIS-C) to those evaluated for MIS-C in the Emergency Department (ED).

We conducted a retrospective review of the medical record of encounters with testing for inflammatory markers in an urban, tertiary care Pediatric ED from March 1, 2020 to July 31, 2020. We abstracted demographic information, laboratory values, selected medications and diagnoses. We reviewed the record for clinical presentation for the subset of patients admitted to the hospital for suspected MIS-C. We then used receiver operating curves and logistic regression to evaluate the utility of candidate laboratory values to predict MIS-C status.

We identified 32 patients with confirmed MIS-C and 15 admitted and evaluated for MIS-C but without confirmation of SARS CoV-2 infection. We compared these patients to 267 encounters with screening laboratories for MIS-C. Confirmed MIS-C patients had an older median age, higher median fever on presentation and were predominantly of Hispanic and non-Hispanic Black race/ethnicity. All children with MIS-C had a C-reactive protein (CRP) >4.5 mg/dL, were more likely to have Brain Natriuretic Peptide >400 pg/mL (OR 10.50, 95%CI 4.40–25.04), D-Dimer >3 μg/mL (7.51, [3.18–17.73]), and absolute lymphocyte count (ALC) <1.5 K/mcL (21.42, [7.19–63.76]). We found CRP >4.5 mg/dL and ALC <1.5 K/mcL to be 86% sensitive and 91% specific to identify MIS-C among patients screened in our population.

We identified that elevated CRP and lymphopenia was 86% sensitive and 91% specific for identification of children with MIS-C.