Total iron-binding capacity

Total iron-binding capacity
The transferrin protein binds free iron and transports it in the blood.
SynonymsTransferrin iron-binding capacity
MedlinePlus003489
LOINC2500-7, 14800-7, 35215-3

Total iron-binding capacity (TIBC) or sometimes transferrin iron-binding capacity is a medical laboratory test that measures the blood's capacity to bind iron with transferrin.[1] Transferrin can bind two atoms of ferric iron (Fe3+) with high affinity. It means that transferrin has the capacity to transport approximately from 1.40 to 1.49 mg of iron per gram of transferrin present in the blood.[2]

It is performed by drawing blood and measuring the maximum amount of iron that it can carry, which indirectly measures transferrin[3] since transferrin is the most dynamic carrier. If TIBC values are known, the transferrin concentration can be estimated with the following formulas:[2]

  • Transferrin (mg/dL) = 0.8 x TIBC (μg of iron/dL) – 43
  • Transferrin (mg/dL) = 0.7 x TIBC (μg of iron/dL)

To measure TIBC in the blood is less expensive than a direct measurement of transferrin.[4][5]

The TIBC should not be confused with the unsaturated iron-binding capacity or UIBC (LOINC 2501-5, 22753-8 & 35216-1). The UIBC is calculated by subtracting the serum iron from the TIBC.[6]

  1. ^ "MedlinePlus Medical Encyclopedia: Total iron binding capacity". Retrieved 2008-12-31.
  2. ^ a b "MrLabTest: Normal TIBC level in the blood". Retrieved 2020-11-19.
  3. ^ Yamanishi H, Iyama S, Yamaguchi Y, Kanakura Y, Iwatani Y (January 2003). "Total iron-binding capacity calculated from serum transferrin concentration or serum iron concentration and unsaturated iron-binding capacity". Clin. Chem. 49 (1): 175–8. doi:10.1373/49.1.175. PMID 12507977.
  4. ^ Kasvosve I, Delanghe J (October 2002). "Total iron binding capacity and transferrin concentration in the assessment of iron status". Clin. Chem. Lab. Med. 40 (10): 1014–8. doi:10.1515/CCLM.2002.176. PMID 12476940. S2CID 45447911.[permanent dead link]
  5. ^ Gambino R, Desvarieux E, Orth M, et al. (December 1997). "The relation between chemically measured total iron-binding capacity concentrations and immunologically measured transferrin concentrations in human serum". Clin. Chem. 43 (12): 2408–12. doi:10.1093/clinchem/43.12.2408. PMID 9439462.
  6. ^ "Iron Transport". Retrieved 2008-12-31.