Ordering Recommendation
Not recommended for routine thyroid screening.
Mnemonic
Methodology
Quantitative Electrochemiluminescent Immunoassay
Performed
Sun-Sat
Reported
Within 24 hours
New York DOH Approval Status
Specimen Required
Serum Separator Tube (SST). Also acceptable: Lavender (K2 EDTA or K3 EDTA), Pink (K2 EDTA), or Green (Lithium Heparin).
Allow specimen to clot completely at room temperature. Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.5 mL)
Refrigerated.
Grossly hemolyzed specimens.
After separation of cells: Ambient: 8 days; Refrigerated: 2 weeks; Frozen: 2 years
Reference Interval
28-41% uptake
Interpretive Data
Thyroxine, Free (Free T4) (0070138) is the preferred test alternative for T3 uptake and Free Thyroxine Index tests.
FDA
Note
T3 uptake is of little clinical value alone; it is used to determine the Free Thyroxine Index.
Hotline History
Hotline History
CPT Codes
84479
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0070135 | T3 Uptake | 3050-2 |
Aliases
- T-Uptake
- T3 Uptake, S
- T3U, Serum
- THBR
- Thyroid Binding Ratio
- Triiodothyronine Uptake, Serum