Chapter 37 SUSPECTED IRON OVERLOAD OR HIGH SERUM FERRITIN
INTRODUCTION
It is important to note that serum ferritin is influenced by liver injury and inflammation, so an elevated serum ferritin does not necessarily indicate increased body iron stores.
IRON METABOLISM
Serum iron studies
Serum iron is included on some routine blood tests of electrolytes and liver enzymes. It is affected by dietary intake, shows diurnal variation, and is not a reliable indicator of iron stores. Transferrin is the major iron transporting protein in the body. Transferrin saturation reflects iron stores and is usually elevated (>50%) before the serum ferritin increases. Transferrin is calculated from the serum iron and total iron binding capacity, which depends on serum transferrin concentration. Measuring fasting transferrin saturations decreases the effects of diet and diurnal variation, and a value of >45% is suggestive of iron overload.