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Transferrin Serum

Anemia Biomarker

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Collection Type: Blood

Body System

Related System: Anemia

Overview

Serum transferrin is a liver-produced glycoprotein that binds and transports iron in the bloodstream to bone marrow and other tissues. The transferrin test measures the circulating concentration of this carrier protein (not to be confused with transferrin saturation, which is a percent). Abnormal transferrin levels are used in evaluating iron status and causes of anemia: high transferrin often reflects iron deficiency; low transferrin can indicate inflammation, chronic disease, liver dysfunction, malnutrition, or nephrotic syndrome. Symptoms prompting testing include fatigue, pallor, shortness of breath, unusual bruising or bleeding, or signs of chronic inflammatory or liver disease. Levels vary with age, pregnancy (often increased), estrogen use, and may be lower in severe illness or advanced age.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Included in the Anemia / iron studies profile.
Symptoms: Persistent fatigue, pallor, breathlessness, weakness, abnormal labs suggesting anemia.
Diagnoses/monitoring: Helps diagnose iron-deficiency anemia versus anemia of chronic disease, monitors response to iron therapy.
Reasons for abnormal levels: Iron deficiency (high transferrin); inflammation, liver disease, malnutrition, nephrotic syndrome (low transferrin).
Biological meaning: High values reflect increased iron-binding capacity when body iron is low; low values reflect reduced hepatic production or protein loss.
Lifestyle/family: Poor diet, heavy alcohol use, chronic inflammatory conditions, or family history of rare hereditary transferrin disorders warrant testing.

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Understanding Test Results

Values above ~360 mg/dL indicate elevated transferrin and usually reflect iron deficiency or increased demand for iron transport (e.g., early iron-deficiency anemia, pregnancy, or estrogen therapy).
Markedly high values (>400 mg/dL) strengthen the likelihood of iron deficiency.
Values below ~200 mg/dL indicate low transferrin and suggest inflammation/chronic disease (negative acute-phase reactant), significant liver synthetic dysfunction, nephrotic protein loss, or severe malnutrition.
Very low levels (<150 mg/dL) point to advanced liver disease, heavy protein loss, or severe systemic inflammation and require further evaluation.
Interpret alongside serum iron, ferritin, TIBC/transferrin saturation, clinical context, and inflammatory markers.

Normal Range

200-360 mg/dL OR 2.0-3.6 g/L

FAQs

Q: What is transferrin serum?

A: Serum transferrin is a liver-produced glycoprotein that binds and transports iron in the bloodstream to cells and bone marrow. It controls free iron levels, reducing oxidative harm. Clinically, transferrin concentration or related tests (TIBC) evaluate iron status: levels typically rise in iron deficiency and fall with inflammation, chronic illness, liver disease, or malnutrition.

Q: What happens when transferrin is low?

A: When transferrin is low, less iron is carried in the blood, reducing delivery to bone marrow and contributing to anemia, fatigue, pallor and reduced exercise tolerance. Low transferrin commonly reflects inflammation, liver disease, malnutrition or protein loss (e.g., nephrotic syndrome). It also lowers total iron‑binding capacity and can mask iron deficiency because iron is sequestered in storage sites.

Q: Why is serum transferrin high?

A: Serum transferrin is often high in iron-deficiency states because the liver makes more to increase iron transport capacity. Other causes include pregnancy and estrogen use (including oral contraceptives), recovery after bleeding or hemolysis, and some liver disorders altering protein synthesis. High transferrin usually occurs with low transferrin saturation and low serum iron.

Q: What is a normal serum transferrin?

A: Normal adult serum transferrin is roughly 200–360 mg/dL (2.0–3.6 g/L), though exact reference ranges vary by laboratory and age. Levels tend to rise in iron deficiency and fall with chronic inflammation, liver disease, or malnutrition. Always interpret results using the laboratory’s reference interval and clinical context; consult your clinician for abnormal values and further testing.

Q: How does low transferrin make you feel?

A: Low transferrin reduces iron transport and often makes you feel like you have iron‑deficiency anemia: persistent fatigue and weakness, pale skin, shortness of breath with exertion, dizziness or lightheadedness, a fast heartbeat, poor concentration, cold hands and feet, and brittle nails or hair loss. It can also signal underlying inflammation, liver disease or malnutrition, so medical evaluation is recommended.

Q: Can low transferrin cause weight gain?

A: Low transferrin itself does not directly cause fat gain. Low levels usually reflect inflammation, malnutrition, liver disease or protein loss (eg, nephrotic syndrome). These underlying conditions can cause fluid retention (edema) or weight changes, not true adipose gain. Treating the underlying cause usually normalizes transferrin and associated weight shifts. See a clinician for evaluation and testing.