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HelpTest Code TIBC Total Iron Binding Capacity, Serum
Specimen Required
Only orderable as part of profile. For more information see SFEC / Iron and Total Iron Binding Capacity, Serum
Patient Preparation:
1. Fasting (12 hours)
2. For 24 hours before collection, patient should not take iron-containing supplements.
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Draw blood before noon (preferred).
2. Within 2 hours of collection, serum gel tubes should be centrifuged.
3. Within 2 hours of collection, red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial.
Secondary ID
2501Useful For
Screening for chronic iron overload diseases, particularly hereditary hemochromatosis
Method Name
Only orderable as part of profile. For more information see SFEC / Iron and Total Iron Binding Capacity, Serum
Turbidity/Calculation
Reporting Name
Total Iron Binding CapacitySpecimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 365 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Transferrin is the plasma iron transport protein that binds iron strongly to keep iron nonreactive in circulation and deliver it to cells with transferrin receptors. The rate of transferrin synthesis in the liver can be altered according to the body’s iron requirements and iron reserves. The circulating concentration increases in response to iron deficiency and decreases in response to iron overload. Transferrin is generally only 25% to 30% saturated with iron. Total iron-binding capacity (TIBC) is estimated from the transferrin concentration using the molecular weight of transferrin, accounting for each transferrin molecule that can bind 2 atoms of iron.
Iron deficiency, iron overload, and anemia of chronic disease are the most prevalent disorders of iron metabolism. Serum iron, TIBC, and percent saturation are widely used for the diagnosis of iron deficiency and iron overload disorders, such as hemochromatosis. Iron concentration and percent saturation decrease with iron deficiency and increase when iron is in excess. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.
Anemia of chronic disease is often observed in patients with autoimmune diseases, chronic kidney diseases, inflammatory bowel disease, and chronic heart failure. It is diagnosed when serum iron concentrations are low despite normal serum ferritin concentrations indicating adequate iron stores. However, in the presence of inflammation, ferritin can mask iron deficiency; therefore, measuring soluble transferrin receptors is suggested.
The biologic variation of iron and, therefore, iron saturation is notable in normal healthy persons and in various clinical disorders owing to both diurnal variation and post-prandial effects. The intraindividual day-to-day variation of iron and iron saturation is approximately 25% to 30%.(1) Recommendations for blood sampling for iron and iron saturation measurements are contradictory; however, minimizing influence of these effects can be accomplished by collecting during the morning after an overnight fast.
Reference Values
Only orderable as part of profile. For more information see SFEC / Iron and Total Iron-Binding Capacity, Serum.
250-400 mcg/dL
Interpretation
Total iron-binding capacity concentrations are elevated in anemia of chronic disease and iron overload conditions.(1)
Total iron-binding capacity concentrations are decreased in iron deficiency, iron deficiency anemia, and iron-refractory iron deficiency anemia.(1)
Cautions
Serum iron concentration, total iron-binding capacity, and percent saturation are widely used for diagnosing iron deficiency. However, serum ferritin is the preferred primary test, as it is a much more sensitive and reliable test for demonstration of iron deficiency.
While measurement of serum iron, total iron-binding capacity, and percent saturation should not be used as the primary test for iron deficiency, they may be helpful when used in conjunction with ferritin and soluble-transferrin receptor analyses, especially in patients with inflammation.
Clinical Reference
1. Swinkels DW. Iron metabolism. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier, 2023:chap 40
2. Kowdley KV, Brown KE, Ahn J, Sundaram V. ACG Clinical Guideline: Hereditary Hemochromatosis. Am J Gastroenterol. 2019;114:1202-1218
3. Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anemia. Lancet. 2016;387:907-916
Method Description
Transferrin:
Anti-transferrin antibodies react with the antigen in the sample to form an antigen/antibody complex. Following agglutination, this is measured turbidimetrically. Addition of polyethylene glycol allows the reaction to progress rapidly to the end point and increases sensitivity. The result is used to calculate the total iron-binding capacity and is not included on the report.(Package insert: TRSF2. Roche Diagnostics; v10.0, 04/2022)
Total Iron-Binding Capacity:
This test calculates the total iron-binding capacity (TIBC) using results obtained from transferrin analysis. The following calculation is performed in the laboratory information system.
TIBC = Transferrin x 1.18
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 2 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
83550
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TIBC | Total Iron Binding Capacity | 2500-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TIBC | Total Iron Binding Capacity | 2500-7 |