What is Known: • Pediatric multisystem inflammatory syndrome temporally associated with COVID-19 (PIMS-TS) is a serious complication of a previous SARS-CoV-2 infection in the group of pediatric patients • Course of the disease may be severe, which may cause long-term complications and the need for longitudinal patient care.

What is New: • Children with higher concentrations of NT-proBNP, troponin, creatinine, TG, CRP, PCT, ferritin, D-dimers and lower hematocrit, PLT, lymphocytes, and EF have a higher risk of a severe course of the disease. • Patients with high concentration of NT-proBNP, troponin, CRP, lactates, ferritin, D-dimers, creatinine and a lower concentration of PLT, albumin, leukocytes; lymphopenia, hyponatremia are at risk for intravenous immunoglobulin resistance.