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Laboratory: Clinical Biochemistry
Test Name:
Test Code: MISC
Clinical Information:
Test Indications: Testing for soluble transferrin receptor (sTfR) is used for the evaluation of iron deficiency in patients with conditions which may cause elevations in ferritin; thus making the correlation to iron status difficult. These include inflammation, infection, chronic diseases such as diabetes mellitus, cystic fibrosis, chronic kidney disease, and certain malignancies. This test should not be used for routine evaluation of patients for iron status when ferritin testing would be appropriate, such as in the absence of confounding pathologies (inflammation, infection, chronic disease, or malignancy).
This test requires prior approval by a Clinical Biochemist.
Click here for the Approval for Test Referral Biochemistry form (F260-11-02)
Patient Preparation Instructions: Patient should fast 12 hours prior to specimen collection. Water can be taken as needed. Infants - Draw prior to next feeding. Document time of last feed.

Anemia of Chronic Disease (ACD) and Anemia of Inflammation (AI) occur due to dysregulation of iron hemostatsis via hepcidin and cytokines. Serum ferritin concentrations in ACD/AI are typically normal or elevated, making it less useful a a measure of iron stores.
Soluble Transferrin Receptor (sTfR) is released into circulation by proteolytic cleavage of the cell-surface Transferrin Receptor on erythroid precusor cells. Iron deficiency results in an increase in Transferrin Receptor expression, which in turn results in an increase in sTfR in serum.
In the instance where iron deficiency anemia is likely being observed concomitantly with ACD/AI, the sTfR-log Ferritin ratio may be used. An sTfR-log Ferritin ratio <1 suggests ACD/AI, whereas a ratio >2 suggests iron deficiency, or iron deficiency in concert with ACD/AI.
1. Weiss G and Goodnough LT. 2005. Anemia of Chronic Disease. N Engl J Med. 352(10):1011.
2. Infusino I, Braga F, Dolci A, and Panteghini M. 2012. Soluble Transferrin Receptor (sTfR) and sTfR/log Ferritin Index for the Diagnosis of Iron-Deficiency Anemia: A Meta-Analysis. Am J Clin Pathol. 138(5): 642-649.
Collection Devices:
Specimen Required:

Serum: 1.0 mL
Pediatric Serum: 1.0 mL

Stability 90 days frozen
Serum: 1.0 mL

Store and ship frozen.
Reference Values:
1.8 - 4.6 mg/L
Within 10 Days
See Also:
More Information:
Specimen Handling: Centrifuge within 2 hours of collection. Store and send frozen to HSC Clinical Chemistry - MS5. Specimen is referred to Mayo Medical Laboratories for analysis.
Test ID: STFR (84238)