CRP and COVID-19: We have found that MIS-C should be suspected even with clear acute appendicitis symptoms and laboratory markers when at least three out of four signs are present: CRP > 55.8 mg, symptoms last three days or longer, presence of febrile fever and any kind of other system involvement is noticed, especially with a known prior recent COVID-19 contact, infection or positive COVID-19 IgG antibody test.