CRP and Hyponatremia: Elevated d-dimer (>3,000 ng/mL fibrinogen equivalent units), C-reactive protein (>3 mg/dL), B-type natriuretic peptide (>400 picograms/mL), and increased fibrinogen (>400 mg/dL) are associated with more severe presentations, and most MIS-C cases have elevations in at least four of these inflammatory biomarkers.5,8 Elevations in troponin, creatine phosphokinase, lactate dehydrogenase, low albumin, and hyponatremia have also been present in other patients with COVID-19 positive MIS-C.