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Test ID: TRSF Transferrin, Serum

Reporting Name

Transferrin, S

Useful For

Screening for chronic iron overload diseases, particularly hereditary hemochromatosis

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

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 aliquoted 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

Reference Values

200-360 mg/dL

Day(s) and Time(s) Performed

Monday through Saturday; Continuously

Test Classification

This test has been cleared, approved or is exempt 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


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.


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%.

Clinical Reference

1. Silverman LM, Christenson RH, Grant GH: Amino acids and proteins. In Textbook of Clinical Chemistry. Edited by NW Tietz. Philadelphia, WB Saunders Company, 1986, pp 519-618

2. Ramsay WN: The determination of the total iron binding capacity of serum. Clin Chim Acta 1997 Mar 18;259(1-2):25-30

3. Tsung SH, Rosenthal WA, Milewski KA: Immunological measurement of transferrin compared with chemical measurement of total iron binding capacity. Clin Chem 1975;21:1063-1066

4. Buffone GJ, Lewis SA, Losefsohn M, Hicks JM: Chemical and immunochemical measurements of total iron binding capacity compared. Clin Chem 1978;24:1788-1791

5. Markowitz H, Fairbanks VF: Transferrin assay and total iron binding capacity. Mayo Clin Proc 1983;58:827-828

6. Szoke D, Panteghini M: Diagnostic value of transferrin. Clin Chim Acta 2012 Aug 16;413(15-16):1184-1189

Analytic Time

Same day/1 day

Method Name

Immunoturbidimetric Assay


If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.

Mayo Clinic Laboratories | Hematology Catalog Additional Information: