Chronic Disease: This is the most likely diagnosis given the low iron and low transferrin levels with a normal ferritin level. Chronic diseases such as chronic infections, inflammation, or malignancies can lead to a decrease in iron and transferrin due to the body's acute phase response, where iron is sequestered and transferrin production is decreased.

Inflammatory Conditions: Conditions like rheumatoid arthritis, lupus, or other autoimmune diseases can cause a decrease in iron and transferrin levels due to chronic inflammation.
Malnutrition: Poor dietary intake of iron and other essential nutrients can lead to low iron levels, although the normal ferritin level suggests that iron stores are not severely depleted.
Gastrointestinal Disorders: Conditions such as celiac disease or Crohn's disease can lead to malabsorption of iron, resulting in low iron levels.

Hemochromatosis: Although less likely given the low iron level, it's crucial not to miss this diagnosis. Some forms of hemochromatosis can present with normal or low iron levels, especially if the patient has been treated or has a milder form of the disease.
Thalassemia: Certain types of thalassemia can present with normal Hgb/Hct but altered iron studies due to the body's attempt to compensate for the defective hemoglobin production.

Atransferrinemia: A rare genetic disorder characterized by the absence or very low levels of transferrin, leading to low iron levels despite normal or elevated ferritin.
Aceruloplasminemia: A rare genetic disorder affecting iron metabolism, characterized by low ceruloplasmin levels, which can lead to low iron levels and neurological symptoms.
Iron Refractory Iron Deficiency Anemia (IRIDA): A rare genetic disorder causing iron deficiency anemia that does not respond to oral iron supplementation, with serum ferritin levels often being normal or elevated.