Can this result diagnose a condition on its own?

No. A laboratory result should be interpreted with related tests, symptoms, medical history, and the reference information on the report.

Which reference range should I use?

Use the reference interval provided by the laboratory that performed the test. Clinical decision cutoffs, when relevant, are shown separately.

When should I discuss the result with a healthcare professional?

Professional assessment is appropriate when a result is markedly outside the reference interval, serious symptoms are present, an abnormality persists or recurs, or follow-up has been recommended.

Information about a laboratory test

High Total Iron-Binding Capacity (TIBC): What Does It Mean?

A high TIBC can be seen in patterns of iron deficiency; it does not establish a diagnosis on its own.

Test summary

Test name: Total Iron-Binding Capacity (TIBC)
Abbreviations: TIBC, TDBK
Category: Iron Metabolism
Panel: Iron Studies
Specimen: Serum
Common units: µg/dL, µmol/L

What does the test measure?

Indirectly measures the capacity of transferrin and other blood proteins to bind iron.

Why is the test ordered?

Used with serum iron and transferrin saturation to help assess patterns that may suggest iron deficiency or iron excess.

Information about a low result

A low TIBC can occur in some inflammatory or chronic-disease states or when transferrin levels are reduced.

Information about a high result

A high TIBC can be seen in patterns of iron deficiency; it does not establish a diagnosis on its own.

Reference and clinical context

Use the reference interval printed on your own laboratory report first. Reference intervals may vary by laboratory, method, unit, age, sex, pregnancy, specimen, and other conditions. Numeric records in this workbook are explicitly labeled as either source-based example reference intervals or clinical decision cutoffs.

Reference range 1

>= 171 – <= 505 µg/dL

Population: Adults
Sex: Male
Specimen: Serum

Example reference interval

MedlinePlus example.

Reference range 2

>= 149 – <= 492 µg/dL

Population: Adults
Sex: Female
Specimen: Serum

Example reference interval

MedlinePlus example.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Low serum iron + high TIBC + low TSAT + low ferritin can form a more consistent pattern of iron deficiency, although diagnosis still requires clinical assessment.

Related specialties

Internal Medicine
Hematology

Frequently asked questions

Sources

Iron Tests — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2024 · Serum iron, transferrin, TIBC, ferritin; combined interpretation · Verified: Aug 11, 2026
Serum iron test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Example adult serum iron, TIBC and iron saturation ranges · Verified: Aug 11, 2026
Total iron binding capacity — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · TIBC definition and interpretation · Verified: Aug 11, 2026