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22932 Transferrin Receptors, Soluble (STFR)

Transferrin Receptors, Soluble (STFR)
Test Code: STFRSO
Synonyms/Keywords
sTfR (soluble transferrin receptor)
Useful For
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
-Evaluating insulin-dependent diabetics who may have iron-deficiency resulting from gastric autoimmunity and atrophic gastritis
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Serum Separator Tube (SST) Red Top Tube (RTT) ​1.0 mL ​0.25 mL
Collection Processing Instructions
​Submit specimen in a plastic vial
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​Frozen (preferred) ​90 days
​Refrigerated ​7 days
​Ambient ​72 hours
Rejection Criteria
Hemolysis Gross
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Sunday​ ​1 day
Immunoturbidimetric Assay​
Reference Lab
Test Information
​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 Range Information
1.8-4.6 mg/L
It is reported that African Americans may have slightly higher values.
Interpretation
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.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​84238
Synonyms/Keywords
sTfR (soluble transferrin receptor)
Ordering Applications
Ordering Application Description
​Centricity ​Transferrin Receptors, Soluble (STFR)
​Cerner None​
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Serum Separator Tube (SST) Red Top Tube (RTT) ​1.0 mL ​0.25 mL
Collection Processing
​Submit specimen in a plastic vial
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​Frozen (preferred) ​90 days
​Refrigerated ​7 days
​Ambient ​72 hours
Rejection Criteria
Hemolysis Gross
Useful For
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
-Evaluating insulin-dependent diabetics who may have iron-deficiency resulting from gastric autoimmunity and atrophic gastritis
Reference Range Information
1.8-4.6 mg/L
It is reported that African Americans may have slightly higher values.
Interpretation
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.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Sunday​ ​1 day
Immunoturbidimetric Assay​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​84238
For most current information refer to the Marshfield Laboratory online reference manual.