Not medically reviewed
Iron and vitamins
Total iron-binding capacity (TIBC)
Not medically reviewed · Content last updated · 1 min read ·
This is the date the draft was written, not a medical review date.
An indirect measure of transferrin: the maximal amount of iron that serum can bind. It rises in iron deficiency as the liver synthesises more transferrin.
Reference interval
| Conventional (µg/dL) | SI (µmol/L) | |
|---|---|---|
| Adults | 250–450 µg/dL | 44.8–80.6 µmol/L |
Specimen: Serum (non-haemolysed) · Conventional × 0.179 = SI
Causes of high values
Iron deficiency, late pregnancy, oral contraceptives and oestrogen therapy, acute hepatitis.
Causes of low values
Anaemia of chronic disease and inflammation, malnutrition and hypoproteinaemia, cirrhosis and other liver disease, nephrotic syndrome, iron overload (haemochromatosis), malignancy.
Pre-analytical and method notes
TIBC is an indirect index of transferrin (transferrin concentration multiplied by about 25 gives a close estimate) and is interpreted with serum iron to give the transferrin saturation. Transferrin is a negative acute-phase protein, so values fall in inflammation. Reference intervals vary by laboratory, method and population; use the interval printed on the report.
References
- Rifai N, Horvath AR, Wittwer CT. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Elsevier, 6th edition (2018) — Tier 3 (textbook)
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. Elsevier — Tier 3 (textbook)
- Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity (WHO/NMH/NHD/MNM/11.1). World Health Organization (2011) — Tier 1 (standards / international bodies)
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