Myoglobin, filtered by the kidneys, appears in the urine when plasma concentrations exceed 1.5 mg/dL.14 Given the lack of association between dark urine, which could be considered indicative of myoglobinuria, and AKI, this observation may suggest that, similar to serum CK, myoglobinuria alone may not suffice to cause AKI in patients with ERM. Here, MB is linked to acute kidney injury.