Iron Studies

An iron panel is a physiology problem, not a collection of isolated flags. Ferritin estimates stored iron; serum iron and TSAT describe circulating iron available for delivery; TIBC approximates transferrin capacity. Hepcidin links these measurements: when iron or inflammation raises hepcidin, ferroportin is blocked and iron remains sequestered in enterocytes and macrophages. Serum iron and TSAT can therefore fall while ferritin remains normal or high. A patient with rheumatoid arthritis, ferritin 75 µg/L, and TSAT 12% may have iron-restricted erythropoiesis despite a ferritin that is not low. In uncomplicated suspected deficiency, Canadian Choosing Wisely guidance generally favours ferritin rather than automatically ordering every component of the full profile; inflammatory disease, CKD, liver disease, or possible overload changes that approach. Read the pattern against the CBC and clinical context, then address both the iron abnormality and its source.