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HelpTest Code TRSF Transferrin, Serum
Reporting Name
Transferrin, SUseful For
Screening for chronic iron overload diseases, particularly hereditary hemochromatosis
Method Name
Immunoturbidimetric Assay
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.6 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Minimum Volume
0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 180 days | ||
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
200-360 mg/dL
Day(s) Performed
Monday through Saturday
CPT Code Information
84466
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TRSF | Transferrin, S | 3034-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| TRSF | Transferrin, S | 3034-6 |
Clinical Information
Transferrin is a glycoprotein with a molecular weight of 79570 daltons. It consists of a polypeptide strand with 2 N-glycosidically linked oligosaccharide chains and exists in numerous isoforms. The rate of synthesis in the liver can be altered in accordance with the body’s iron requirements and iron reserves. Transferrin is the iron transport protein in serum. In cases of iron deficiency, the degree of transferrin saturation appears to be an extremely sensitive indicator of functional iron depletion. The ferritin levels are depressed when there is a deficiency of storage iron. In sideropenia, an iron deficiency can be excluded if the serum transferrin concentration is low, as in inflammation or less commonly, in cases of ascorbic acid deficiency. In screening for hereditary hemochromatosis, transferrin saturation provides a better indication of the homozygous genotype than does ferritin. The treatment of anemia with erythropoietin in patients with renal failure is only effective when sufficient depot iron is present. The best monitoring procedure is to determine transferrin saturation during therapy. Transferrin saturation in conjunction with ferritin gives a conclusive prediction of the exclusion of iron overloading in patients with chronic liver disease.
Interpretation
Serum iron, total iron-binding capacity (TIBC), and percent saturation are useful only in screening for chronic iron overload diseases, particularly hereditary hemochromatosis. Although serum iron, TIBC, and percent saturation are widely used for the diagnosis of iron deficiency, serum ferritin is a much more sensitive and reliable means of demonstrating iron deficiency.
In hereditary hemochromatosis, serum iron is usually above 150 mcg/dL and percent saturation exceeds 60%.
In advanced iron overload states, the percent saturation often exceeds 90%.
Cautions
Measurement of serum iron, iron-binding capacity, and percent saturation should not be used as the primary test for iron deficiency. It may be helpful when used in conjunction with ferritin and soluble transferrin receptor testing, especially in patients with inflammation.
Method Description
Antitransferrin 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.(Package insert: Roche TRSF2 reagent. Indianapolis, IN, 2005)