A 34-year-old woman presents with complaints of persistent f…
A 34-year-old woman presents with complaints of persistent fatigue, shortness of breath on exertion, and observed pallor over the past few months. Her menstrual periods have been notably heavy. A complete blood count reveals a hemoglobin of 9.2 g/dL, MCV of 72 fL (low), and MCH of 23 pg (low), consistent with microcytic, hypochromic anemia. To specifically assess her iron stores and confirm iron deficiency as the cause of her anemia, which of the following laboratory tests is the MOST sensitive and specific