Age-adjusted NT-proBNP could help in the early identification and follow-up of children at risk for severe multisystem inflammatory syndrome associated with COVID-19 (MIS-C)

Table 1 World Health Organization case definition for Multisystem inflammatory syndrome in children

All criteria must be met
Age 0 to 19 yr
Fever ≥ 3 d
Clinical signs of multisystem involvement (at least 2 of the following):
Rash, bilateral non purulent conjunctivitis, or mucocutaneous inflammation (oral, hands, or feet)
Hypotension or shock
Cardiac dysfunction, pericarditis, valvulitis, or coronary abnormalities (including echocardiographic findings or elevated troponin/BNP)
Evidence of coagulopathy (prolonged PT or PTT; elevated D-dimer)
Acute gastrointestinal symptoms (diarrhea, vomiting, or abdominal pain)
Elevated markers of inflammation (e.g., ESR, CRP, or procalcitonin)
No other obvious microbial cause of inflammation, including bacterial sepsis and staphylococcal/streptococcal toxic shock syndromes
Evidence of SARS-CoV-2 infection with any of the following:
Positive SARS-CoV-2 RT-PCR
Positive serology
Positive antigen test
Contact with an individual with COVID-19 either laboratory confirmation of SARS-CoV-2 infection by RT-PCR, serology, or antigen test, or known COVID-19 exposure within 4 weeks before symptom onset

MIS-C: Multisystem inflammatory syndrome in children; PT: Prothrombin time; PTT: Partial thromboplastin time; ESR: Erythrocyte sedimentation rate; CRP: C reactive protein; RT-PCR: Real time polymerase chain reaction; COVID-19: Coronavirus disease 2019; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2.