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HelpTest ID FEC Iron and Total Iron-Binding Capacity, Serum
Useful For
Screening for chronic iron overload diseases, particularly hereditary hemochromatosis
Serum iron, total iron-binding capacity, and percent saturation are widely used for the diagnosis of iron deficiency. However, serum ferritin is a much more sensitive and reliable test for demonstration of iron deficiency.
Testing Algorithm
See Hereditary Hemochromatosis Algorithm in Special Instructions.
Special Instructions
Method Name
Immunoturbidimetric Assay
Reporting Name
Iron and Total Fe Binding Cap, SSpecimen Type
SerumContainer/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 1 mL
Collection Instructions:
1. Fasting (12 hours)
2. Draw blood before 12 noon (preferred).
3. Serum gel tubes should be centrifuged within 2 hours of collection.
4. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.
Additional Information:
1. Patient’s age and sex are required.
2. Iron-containing supplements should be avoided for 24 hours prior to draw.
Forms: If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/benign-hematology-test-request-form.pdf)
Specimen Minimum Volume
0.50 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | 180 days |
Clinical Information
Ingested iron is absorbed primarily from the intestinal tract and is temporarily stored in the mucosal cells as Fe(III)-ferritin. Ferritin provides a soluble protein shell to encapsulate a complex of insoluble ferric hydroxide-ferric phosphate. On demand, iron is released into the blood by mechanisms that are not clearly understood, to be transported as Fe(III)-transferrin.
Transferrin is the primary plasma iron transport protein, which binds iron strongly at physiological pH. Transferrin is generally only 25% to 30% saturated with iron. The additional amount of iron that can be bound is the unsaturated iron-binding capacity (UIBC). The total iron binding capacity (TIBC) can be indirectly determined using the sum of the serum iron and UIBC. Knowing the molecular weight of the transferrin and that each molecule of transferrin can bind 2 atoms of iron, TIBC and transferrin concentration is interconvertible.
Percent saturation (100 x serum iron/TIBC) is usually normal or increased in persons who are iron deficient, pregnant, or are taking oral contraceptive medications. Persons with chronic inflammatory processes, hemochromatosis, or malignancies generally display low transferrin.
Reference Values
IRON
Males: 50-150 mcg/dL
Females: 35-145 mcg/dL
TOTAL BINDING CAPACITY
250-400 mcg/dL
PERCENT SATURATION
14-50%
Cautions
Measurement of serum iron, iron-binding capacity, and percent saturation should not be used as a test for iron deficiency. It is often unreliable for this purpose.
Day(s) Performed
Monday through Saturday; Continuously
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. 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
83540-Iron
83550-Iron-binding capacity