Differential Diagnosis for Low Transferrin Level with Normal TIBC, Normal Serum Iron, and Normal H&H

• Single Most Likely Diagnosis
  • Chronic disease or inflammation: This is the most likely diagnosis because chronic diseases, such as chronic infections, autoimmune disorders, or cancer, can lead to a decrease in transferrin levels due to the body's acute phase response, where transferrin acts as a negative acute phase protein. Its levels decrease in response to inflammation.
• Other Likely Diagnoses
  • Malnutrition: Transferrin is a protein, and its synthesis can be impaired in states of malnutrition, leading to low levels.
  • Liver disease: The liver produces transferrin, so liver dysfunction can result in decreased transferrin levels. However, this would typically be accompanied by other abnormalities in liver function tests.
  • Nephrotic syndrome: Significant protein loss through the urine can lead to low levels of transferrin, among other proteins.
• Do Not Miss Diagnoses
  • Hemochromatosis: Although less likely given the normal serum iron and TIBC, it's crucial not to miss this diagnosis. In some cases, especially early in the disease, serum iron and TIBC might not be significantly elevated or decreased, respectively. However, transferrin saturation would typically be high.
  • Thalassemia: Certain types of thalassemia can present with low transferrin levels due to the body's attempt to increase iron absorption and utilization for erythropoiesis. Normal H&H does not rule out thalassemia trait.
• Rare Diagnoses
  • Genetic disorders affecting transferrin: Such as atransferrinemia, a rare genetic disorder characterized by very low or absent transferrin levels, leading to iron overload and other complications.
  • Certain medications: Some medications can affect transferrin levels, though this is less common and would typically be considered after other causes have been ruled out.