Comparative Analysis of Routine Blood Laboratory Tests in Multisystem Inflammatory Syndrome in Children (MIS-C) and Kawasaki Disease Among White and Black Children

To assess racial differences in disease presentation and blood laboratory parameters in improving diagnostic accuracy and management strategies for Kawasaki Disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C), a retrospective study was conducted at Children’s of Alabama. Patients with KD, admitted between January 2000 and January 2020 and those with MIS-C, between January 2021 and December 2022 were identified using the Children’s of Alabama hospital’s administrative database yielding 591 records. KD patients were defined using the American Heart Association (AHA) diagnostic criteria and MIS-C patients were defined based on CDC definition. Only patients with a parent-reported race of Black or White were included. All patients with the eight key blood laboratory parameters, Hematocrit, C-Reactive Protein (CRP), Aspartate Aminotransferase (AST), Alanine Transaminase (ALT), Creatinine, Sodium, Platelet count, and Erythrocyte Sedimentation Rate (ESR) at the acute phase of the disease were included in the study. Age specific range of clinical values were assessed to define abnormal measurements. Race-specific analysis was conducted using descriptive statistics (mean, median and standard deviation). A logistic regression model using sum of abnormal lab parameters was applied to distinguish MIS-C from KD within Black and White populations. MIS-C patients were older than KD cases across both racial groups (median age 10 years vs. 3.36 years). MIS-C showed significantly elevated inflammatory markers (CRP, AST, ALT) compared to KD, suggesting a heightened systemic inflammatory response. Kidney dysfunction (elevated creatinine) was more common in Black MIS-C patients, indicating possible racial disparities in disease severity. The odds of developing MIS-C increased by 2.9 times with the total number of lab tests below normal range, whereas an increase in the number of lab tests above normal range decreased MIS-C likelihood (OR = 0.54; p = 0.046). The findings showed measurable laboratory differences between White and Black KD and MIS-C patients.