Ferumoxytol is a superparamagnetic iron oxide particle encapsulated by a semisynthetic carbohydrate with properties that can be used by the nephrologist for diagnosis and therapy. Ferumoxytol is approved by the US Food and Drug Administration for treating iron deficiency anemia in the setting of chronic kidney disease, but not for clinical diagnostic imaging. It has gained appeal as a magnetic resonance imaging contrast agent in patients with estimated glomerular filtration rates