ARUP's Laboratory Test Directory
| 0070135: T3 Uptake |
| Test Mnemonic: T3 UP | |
|
Methodology: Electrochemiluminescent Immunoassay
Performed: Sun-Sat Reported: Within 24 hours |
| Specimen Required: | |
|
Collect: One 4 mL SST. Also acceptable: One 4 mL PST, one 3 mL lavender (EDTA), pink (K2 EDTA), or green (sodium or lithium heparin).
Transport: 1 mL serum or plasma at 2-8°C. (Min: 0.5 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.3 mL serum or plasma at 2-8°C. Remarks: Allow serum to clot completely at room temperature. Separate serum or plasma from cells ASAP. Unacceptable Conditions: Grossly hemolyzed specimens. Stability: After separation of cells: Ambient: 24 hours; Refrigerated: 8 days; Frozen: 3 months |
|
| Reference Interval: |
| 28-41% uptake |
| Note: | |
| T3 uptake is of little clinical value alone; it is used to determine the Free Thyroxine Index. |
| CPT Code(s): | |
| 84479 |