Table 2. MIS-C definition by CSTE/CDC case definition for MIS-C; 2022.12

MIS-C definition [11]	Case 1	Case 2
Clinical criteriaAll of the following criteria must be met1. Person aged < 212. Fever (temperature ≥ 38.0 °C)3. Clinical severity requiring hospitalization or resulting in death4. Evidence of systemic inflammation (CRP ≥ 3 mg/dL)5. New onset manifestations in at least two of the following categories: 1) Cardiac involvement  - Left ventricular ejection fraction < 55% OR  - Coronary artery dilatation, aneurysm, ectasia OR  - Troponin elevated above laboratory normal range 2) Mucocutaneous involvement  - Rash OR  - Inflammation of the oral mucosa OR  - Conjunctivitis or conjunctival injection OR  - Extremity findings (e.g., erythema or edema) 3) Shock 4) Gastrointestinal involvement  - Abdominal pain OR Vomiting OR diarrhea 5) Hematologic involvement  - Platelet count < 150,000 cells/μL OR  - Absolute lymphocyte count (ALC) < 1,000 cells/μL	1. F/9 years2. Fever for 7 days3. Yes4. CRP 46.6 mg/L5. Cardiac involvement (LVEF 43%), mucocutaneous involvement (truncal rash, conjunctivitis, hand, feet swelling), gastrointestinal involvement (abdominal pain, vomiting)	1. F/8 years2. Fever for 5 days3. Yes4. CRP 1.7 mg/L5. Cardiac involvement (LVEF 43%, troponin elevation)
No other obvious microbial cause of inflammation	Mycoplasma Ab (+)Rhinovirus (+)Metapneumovirus (+)
Laboratory criteriaEvidence of SARS-CoV-2 infection, demonstrated by detection of viral RNA, antigen, or specific antibodies in clinical or post-mortem specimens within 60 days prior to or during hospitalization1)	SARS-CoV-2 Ab (+)	RT-PCR (+)SARS-CoV-2 Ab (+)
Epidemiologic linkage Close contact2) with a confirmed or probable case of COVID-19 disease in the 60 days prior to hospitalization

Includes a positive serology test regardless of COVID-19 vaccination status. Detection of anti-nucleocapsid antibody is indicative of SARS-CoV-2 infection, while anti-spike protein antibody may be induced either by COVID-19 vaccination or by SARS-CoV-2 infection.
Close contact is generally defined as being within 6 feet for at least 15 minutes (cumulative over a 24-hour period).
LVEF: left ventricular ejection fraction; CSTE/CDC: construction safety training and education/Centers for Disease Control and Prevention; LV: left ventricular; RT-PCR: reverse transcription polymerase chain reaction; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.