CRP and Hyponatremia: Initial laboratory criteria for strongly suspected MIS-C [9] as elevated C-reactive protein (CRP) ≥30 mg/L and/or erythrocyte sedimentation rate (ESR) >40 mm/h plus lymphopenia <1000 or thrombocytopenia <150 × 103 or hyponatraemia <135 mmol/L were met in all 13 MIS-C patients.