Test Catalog

Test Id : STFR1

sTfR (Soluble Transferrin Receptor), Serum

Test Catalog

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

Aiding in the diagnosis of iron deficiency anemia in patients with chronic disease

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

Chemiluminescent Immunoassay

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

Yes

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

Soluble Transferrin Receptor (sTfR)

Aliases
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

Serum

Ordering Guidance

This test should not be used for routine iron status evaluation for patients without confounding pathologies (such as inflammation, infection, chronic disease, or malignancy). For such cases order FERR1 / Ferritin, Serum.

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

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL Serum

Collection Instructions:

1. Within 2 hours of collection, centrifuge the specimen.

2. For red-top tubes, aliquot serum into a plastic vial prior to sending.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

Serum: 0.6 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 Refrigerated (preferred) 7 days
Ambient 7 days
Frozen 90 days

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

Aiding in the diagnosis of iron deficiency anemia in patients with chronic disease

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

Transferrin receptor (TfR) mediates iron uptake by cells. It is a transmembrane, disulfide-linked dimer of two identical subunits that binds and internalizes diferric transferrin, thereby delivering iron to the cell cytosol. When a cell needs iron, TfR expression increases to facilitate iron uptake. Since the major use of iron is for hemoglobin synthesis, about 80% of total TfR is located on erythroid progenitor cells.

 

Soluble transferrin receptor (sTfR) is the product of the proteolysis of TfR at a specific site in the extracellular domain, which leads to monomers that are measurable in serum. A constant relationship is reported between total TfR and the concentration of sTfR in serum. Thus, the concentration of sTfR in serum is an indirect measure of total TfR.

 

The concentration of sTfR in serum elevates with iron deficiency and hyperplastic erythropoiesis (eg, hemolytic anemia, beta-thalassemia, polycythemia) and decreases in subjects with hypoplastic erythropoiesis (eg, chronic renal failure, aplastic anemia or post-transplant anemia).

 

Anemia of chronic disease (ACD) and iron deficiency anemia (IDA), the most common forms of anemia, are differentiated primarily by estimates of iron status. Standard measures of iron status, such as ferritin, total iron-binding capacity, and serum iron are confounded by chronic disease, which leads to equivocal results.

Measurement of sTfR is valuable as an indicator of iron deficiency in individuals with chronic disease (eg, inflammatory diseases and infections) as sTfR is minimally affected by proinflammatory cytokines found in ACD patients, which provides an advantage over serum ferritin in the evaluation of iron status and erythropoiesis.(1,2)

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.

0.63-2.64 mg/L

 

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

Interpretation
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.

Cautions
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 (FERR1 / Ferritin, Serum) would be appropriate, such as in the absence of confounding pathologies (inflammation, infection, chronic disease, or malignancy).

 

Soluble transferrin receptor assays are not standardized, therefore results from different assays should not be used interchangeably.(3)

 

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

 

Race-based differences in sTfR have been observed with Black subjects having 9% higher values compared to non-Black subjects.(4)

 

Altitude-based differences in sTfR have been observed with subjects residing at high altitude having concentrations 9% higher than those nearer to sea level.(4)

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

1. Vazquez-Lopez MA, Lopez-Ruzafa E, Ibanez-Alcalde M, Martín-Gonzalez M, Bonillo-Perales A, Lendinez-Molinos F. The usefulness of reticulocyte haemoglobin content, serum transferrin receptor and the sTfR-ferritin index to identify iron deficiency in healthy children aged 1-16 years. Eur J Pediatr. 2019;178(1):41-49

2. Mast AE, Blinder MA, Gronowski AM, Chumley C, Scott MG. Clinical utility of the soluble transferrin receptor and comparison with serum ferritin in several populations. Clin Chem. 1998;44(1):45-51

3. Bohn MK, Berman M, Ali S, et al. Evaluation of a new soluble transferrin receptor assay and comparison to three measurement procedures. Clin Biochem. 2025;135:110862. doi:10.1016/j.clinbiochem.2024.110862

4. Allen J, Backstrom KR, Cooper JA, et al. Measurement of soluble transferrin receptor in serum of healthy adults. Clin Chem. 1998;44(1):35-39

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

The Access sTfR (soluble transferrin receptor) assay is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of sTfR levels in human serum using the Access Immunoassay Systems. The Access sTfR assay is a sequential two-step immunoenzymatic ("sandwich") assay. A sample is added to a reaction vessel along with paramagnetic particles coated with anti-sTfR antibody. During incubation, the sTfR antigen in the sample binds to the immobilized anti-sTfR antibody on the solid phase. Alkaline phosphatase-conjugated anti-sTfR antibody is then added and reacts with a different antigenic site on the sTfR molecule. After incubation, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, chemiluminescent substrate is added to the vessel, and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of analyte in the sample. Analyte concentration is automatically determined from a stored calibration.(Package insert: Access sTfR. Beckman Coulter; 01/2025)

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

No

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 Friday

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.

1 to 3 days

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

1 week

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

Mayo Clinic Laboratories - Rochester Main Campus
CLIA Number: 24D0404292

Fees :
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 account representative. 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.

84238

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
STFR1 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.
STFR1 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

Test Update Resources

Change Type Effective Date
New Test 2026-02-17