Transferrin
Overview
Transferrin measures serum glycoprotein that binds and transports iron from sites of absorption and storage to erythroid precursors for hemoglobin synthesis. It maintains iron homeostasis and delivers iron via transferrin receptor-mediated endocytosis. Low levels indicate iron deficiency, malnutrition, or chronic inflammation (negative acute phase reactant), while high levels suggest iron overload or genetic transferrin deficiency; clinically useful for assessing iron deficiency anemia when ferritin is unreliable and calculating transferrin saturation with serum iron.
Clinical Use Cases
- Evaluating iron deficiency anemia with low transferrin saturation.
- Differentiating iron deficiency from anemia of chronic disease.
- Monitoring nutritional status in malnutrition or liver disease.
- Assessing hereditary atransferrinemia (rare).
- Calculating total iron-binding capacity (TIBC).
Specimen Types
- Serum.
- Plasma (heparin).
Measurement Methods
- Immunoturbidimetry/nephelometry.
- Immunoassay.
- Automated clinical chemistry analyzers.
Test Preparation and Influencing Factors
- Fasting preferred (8-12 hours).
- Iron deficiency increases transferrin; inflammation decreases it.
- Oral contraceptives, pregnancy elevate levels.
- Liver disease, nephrotic syndrome lower transferrin.
- Recent iron therapy transiently affects results.
Synonyms
- Siderophilin.
- Trf.
- Total iron-binding capacity (TIBC, calculated).