Iron Deficiency Anemia (IDA): The patient's low iron level (62 µg/dL), low transferrin saturation (20%), and low ferritin (15 µg/dL) are all indicative of iron deficiency anemia. The microcytic anemia (MCV of 67.6 fL) further supports this diagnosis, as iron deficiency typically leads to smaller than normal red blood cells.

Anemia of Chronic Disease: Although the patient's iron studies suggest iron deficiency, anemia of chronic disease can also present with low iron and ferritin levels due to inflammation. However, the transferrin saturation and the clinical context would help differentiate between these two conditions.
Thalassemia Trait: Given the patient's microcytic anemia, thalassemia trait is a consideration, especially if there's a family history. However, iron studies would typically be normal or show iron overload in thalassemia, making IDA more likely in this case.

Celiac Disease: This condition can lead to iron deficiency anemia due to malabsorption. It's crucial to consider and rule out celiac disease, as it requires a specific dietary intervention.
Heavy Menstrual Bleeding: Although not directly diagnosable from the lab values, heavy menstrual bleeding is a common cause of iron deficiency anemia in females and should be assessed through clinical history.
Gastrointestinal Blood Loss: Any source of chronic blood loss, such as ulcers or colon cancer (though rare in this age group), could lead to iron deficiency anemia and must be considered.

Sideroblastic Anemia: A group of disorders characterized by the accumulation of iron in the mitochondria of red blood cell precursors, leading to microcytic anemia. However, this would typically present with elevated iron stores, not deficiency.
Pregnancy: Although rare at 17, pregnancy can lead to iron deficiency anemia due to increased demand. A pregnancy test should be considered as part of the initial evaluation, especially if there's a possibility of sexual activity.