ARUP's Laboratory Test Directory

Soluble Transferrin Receptor : 0070283

Mnemonic: STR

Methodology: Quantitative Immunoturbidimetry
Performed: Sun-Sat
Reported: Within 24 hours
Specimen Required: Collect: Serum separator tube or plasma separator tube. Also acceptable: green (sodium or lithium heparin), lavender (EDTA), or pink (K2EDTA).

Specimen Preparation: Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.3 mL)

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Contaminated, severely hemolyzed, icteric, or lipemic specimens.

Stability (collection to initiation of testing): After separation from cells: Ambient: 72 hours; Refrigerated: 1 week; Frozen: 1 month (avoid repeated freeze/thaw cycles)

Reference Interval:
Male - 18 years & older: 2.2-5.0 mg/L
Female - 18 years & older: 1.9-4.4 mg/L
Interpretive Data: People of African descent and those residing at 5,200 feet (1,600 meters) above sea level were found to have a 6% higher normal value.  These differences were additive.  Reference intervals have not been established for pregnant females, patients under 18 years of age, and recent or frequent blood donors.

Serum soluble transferrin receptor increases in iron deficiency and is usually unaffected by chronic disease states.  In general, to increase sensitivity and specificity, the measurement of serum soluble transferrin receptor should be performed in combination with other tests of iron status, including ferritin, TIBC, and serum iron (refer to table below).
 
 Tests for Changes in: Iron Deficiency Anemia Anemia of Chronic Disease Iron Deficiency & Anemia of Chronic Disease
Ferritin Iron Stores Low High Normal or High
TIBC Iron Status High Low Normal or High
Serum Iron Iron Status Low Low Low
sTfR Iron Status High Normal High

CPT Code(s): 84238
Cross References: Transferrin Receptor Level (Soluble Transferrin Receptor)