Test Catalog

Test Id : STFR

Soluble Transferrin Receptor (sTfR), Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of suspected iron deficiency in patients who may have inflammation, infection, or chronic disease and other conditions in which ferritin concentration does not correlate with iron status, including:

-Cystic fibrosis patients who frequently have inflammation or infections(1-2)

-Evaluating insulin-dependent diabetics who may have iron-deficiency resulting from gastric autoimmunity and  atrophic gastritis(3)

Method Name
A short description of the method used to perform the test

Immunoturbidimetric Assay

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Soluble Transferrin Receptor (sTfR)

Lists additional common names for a test, as an aid in searching

sTfR (soluble transferrin receptor)

Specimen Type
Describes the specimen type validated for testing


Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 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
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.25 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 90 days
Refrigerated 7 days
Ambient 72 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluation of suspected iron deficiency in patients who may have inflammation, infection, or chronic disease and other conditions in which ferritin concentration does not correlate with iron status, including:

-Cystic fibrosis patients who frequently have inflammation or infections(1-2)

-Evaluating insulin-dependent diabetics who may have iron-deficiency resulting from gastric autoimmunity and  atrophic gastritis(3)

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Iron uptake into cells is mediated through internalizing iron-transferrin complexes. The iron-transferrin complex binds to transferrin receptors present on the external face of the plasma membrane, and is internalized through endosomes with ultimate release of iron into the cytoplasm. Plasma membrane-bound transferrin receptor is released by proteolytic cleavage of the extracellular domain, resulting in the formation of a truncated soluble transferrin receptor (sTfR) that circulates freely in the blood.


The concentration of sTfR is an indicator of iron status. Iron deficiency causes overexpression of transferrin receptor and sTfR levels, while iron repletion results in decreased sTfR levels. While ferritin measurement is the accepted method for assessment of iron deficiency, ferritin is an acute-phase reactant and elevates in response to processes that do not correlate with iron status, including inflammation, chronic disease, malignancy, and infection. sTfR is not an acute-phase reactant and the interpretation of iron status using sTfR measurement is not affected by these confounding pathologies.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

1.8-4.6 mg/L

It is reported that African Americans may have slightly higher values.

Provides information to assist in interpretation of the test results

Soluble transferrin receptor (sTfR) concentrations are inversely related to iron status; sTfR elevates in response to iron deficiency and decreases in response to iron repletion.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The soluble transferrin receptor (sTfR) immunoassay should not be used for the routine clinical evaluation of patients for iron status when ferritin immunoassay (FERR / Ferritin, Serum) would be appropriate, such as in the absence of confounding pathologies (inflammation, infection, chronic disease, or malignancy).


Patients with hemolysis and recent blood loss may have falsely elevated sTfR levels.


sTfR is elevated in patients with thalassemia and sickle cell disease. Caution should be exercised in managing anemia in these individuals based on the sTfR test results.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Cook JD, Skikne BS, Baynes RD: Serum transferrin receptor. Ann Rev Med 1993;44:63-74

2. Keevil B, Rowlands D, Burton I, Webb AK: Assessment of iron status in cystic fibrosis patients. Ann Clin Biochem 2000;37:662-665

3. De Block CEM, Van Capenhout CM, De Leeuw IH, et al: Soluble transferrin receptor level: a new marker of iron deficiency anemia, a common manifestation of gastric autoimmunity in type 1 diabetes. Diabetes Care 2000;23:


4. Mast AE, Blinder MA, Gronowski AM, et al: Clinical utility of the soluble transferrin receptor and comparison with serum ferritin in several populations. Clin Chem 1998;44:45-51

5. Rees DC, Williams TN, Maitland K, et al: Alpha thalassaemia is associated with increased soluble transferrin receptor levels. Br J Haematol 1998;103:365-369

6. Duits AJ, Roker RA, van Endt T, et al: Erythropoiesis and Serum sVCAM-1 levels in adults with sickle cell disease. Ann Hematol 2003;82:171-174

Method Description
Describes how the test is performed and provides a method-specific reference

Latex-bound anti-sTfR antibodies react with the antigen in the sample to form an antigen/antibody complex. Following agglutination, the complex is measured turbidimetrically on a Roche P Modular.(Package insert: The Tina-quant Soluble Transferrin Receptor Immunoturbidimetric assay for the in vitro quantitative determination of soluble transferrin receptor. Roche Corporation, Indianapolis, IN 46250, 2001)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Sunday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 2 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Stored Serum 1 week

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
STFR Soluble Transferrin Receptor (sTfR) 30248-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
STFR Soluble Transferrin Receptor (sTfR) 30248-9

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports