What is the gold standard for confirming iron deficiency?

The gold standard for confirming iron deficiency is a bone marrow biopsy, particularly when looking for the presence of iron stores. In a healthy individual, bone marrow is expected to have adequate iron stores, which can be assessed histologically. If iron deficiency is present, there will be a marked decrease or absence of iron deposits in the marrow.

While serum ferritin measurement is commonly used and reflects the body’s iron stores, it can be influenced by inflammatory states and may not always accurately represent iron deficiency. Similarly, transferrin saturation and soluble transferrin receptor assays provide useful insights into iron metabolism but do not definitively confirm iron deficiency at the tissue level in the same way that a bone marrow biopsy does.

Therefore, when direct evidence of iron stores is required to confirm a diagnosis of iron deficiency, a bone marrow biopsy serves as the definitive method.