CRP and appendicitis: We found that if the patient suspected of acute appendicitis had three out of four criteria: CRP > 55.8 mg/L, duration of symptoms lasting three days or more, symptoms of other organ system involvement (even without prior testing such symptoms as a skin rash, conjunctivitis, peripheral lymphadenopathy and so on) as well as a history of a febrile fever of at least 38 degrees Celsius—he or she should be examined and tested for possible MIS-C, especially with a known recent prior COVID-19 infection, contact or a positive COVID-19 IgG test.