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TIBC

Anemia Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Anemia

Overview

Total Iron Binding Capacity (TIBC) measures the blood’s capacity to bind iron with transferrin, the primary iron-transport protein. The test estimates how much transferrin is available to carry iron and is used with serum iron and ferritin to evaluate iron status. Abnormal results can suggest iron deficiency (high TIBC), anemia of chronic disease or inflammation (low TIBC), or iron overload (low TIBC). Symptoms prompting testing include fatigue, weakness, pallor, shortness of breath, pica, or unexplained microcytic anemia. Age and sex affect results: menstruating women and pregnant people often show higher TIBC (due to lower iron stores), while chronic illness, liver disease or older age may lower TIBC.

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Test Preparation

Overnight fasting is preferred but not mandatory
Avoid iron supplements for at least 24 hours prior to sample collection

Why Do I Need This Test

Profile: Anemia (iron studies) profile - Symptoms: fatigue, pallor, breathlessness, pica, brittle nails - Diagnoses/monitoring: iron deficiency anemia, anemia of chronic disease, hemochromatosis, response to iron therapy - Causes of abnormal levels: inflammation, malnutrition, liver disease, pregnancy, blood loss, genetic iron overload - Biological meaning: high TIBC = more transferrin available (usually low iron stores); low TIBC = decreased transferrin production or iron overload - Lifestyle/family: poor diet, heavy menstrual bleeding, chronic alcohol use, family history of hereditary hemochromatosis

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Understanding Test Results

Values below ~240 µg/dL (<42.9 μmol/L) are considered low and commonly indicate chronic inflammation, infection, liver disease, nephrotic syndrome, or iron overload (e.g., hereditary hemochromatosis) low transferrin production reduces TIBC.
Normal range is about 250–450 µg/dL (44.7–80.5 μmol/L).
Values above ~450 µg/dL (>80.5 μmol/L) are high and typically reflect iron deficiency (reduced iron stores lead to increased transferrin production), pregnancy, or use of certain hormones/contraceptives.
Interpret TIBC with serum iron and transferrin saturation: low transferrin saturation (<15%) with high TIBC supports iron deficiency; high saturation (>45%) with low TIBC suggests iron overload.
Clinical context and ferritin are essential for accurate diagnosis.

Normal Range

250-450 µg/dL OR 44.7-80.5 μmol/L

FAQs

Q: What happens if TIBC is high?

A: High total iron‑binding capacity (TIBC) usually indicates low body iron stores the liver makes more transferrin to capture scarce iron. It commonly reflects iron‑deficiency anemia from poor intake, chronic blood loss, or pregnancy/estrogen therapy. Symptoms include fatigue, pallor, and weakness. Clinicians interpret high TIBC alongside serum iron and ferritin to confirm iron deficiency and guide treatment.

Q: Why is TIBC increased in iron deficiency?

A: In iron deficiency, the liver increases production of transferrin to capture and transport scarce iron, which raises the number of available iron‑binding sites measured as TIBC. Serum iron falls while transferrin rises, so transferrin saturation decreases despite higher TIBC. This compensatory rise aims to mobilize and deliver the limited iron to tissues.

Q: What is the difference between Tibc and transferrin?

A: TIBC (total iron‑binding capacity) is a lab measure of how much iron blood proteins can bind; it’s an indirect estimate of transferrin availability. Transferrin is the main iron‑transport protein itself. TIBC is reported in micrograms per deciliter and correlates closely with transferrin, which can be measured directly in mg/dL. Both vary with iron deficiency and inflammation.

Q: What is the normal level of TIBC?

A: Normal total iron‑binding capacity (TIBC) in adults is roughly 250–450 µg/dL (about 45–80 µmol/L). Reference ranges can vary between laboratories, and values tend to be higher in iron deficiency and lower with inflammation, chronic disease, or malnutrition. Interpret results with clinical context and laboratory-specific reference ranges; consult a clinician for abnormal values.

Q: What cancers cause high TIBC?

A: Cancers don’t usually directly raise TIBC; most malignancies cause inflammation and lower TIBC. High TIBC occurs when iron deficiency develops from chronic blood loss commonly due to gastrointestinal tumors (colorectal, gastric, esophageal) or gynecologic cancers with heavy uterine bleeding. Thus elevated TIBC suggests iron deficiency from bleeding (including cancer-related bleeding), not the tumor itself.

Q: How to treat high TIBC?

A: High TIBC usually reflects iron deficiency. Treat the cause: replace iron (oral ferrous salts providing ~100–200 mg elemental iron daily, or IV iron if severe/intolerant), boost dietary iron and vitamin C, and identify/control blood loss (eg, GI or menstrual). Avoid antacids/calcium around dosing. Recheck ferritin, transferrin saturation and hemoglobin to monitor response and duration.