ARUP's Laboratory Test Directory
| 0070138: Thyroxine, Free (Free T4) |
| Test Mnemonic: FT4 | |
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Methodology: Electrochemiluminescent Immunoassay
Performed: Sun-Sat Reported: Within 24 hours |
| Specimen Required: | |
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Collect: One 4 mL SST or PST. Also acceptable: green (sodium or lithium heparin) or lavender (EDTA).
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: 1 week; Frozen: 1 month |
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| Reference Interval: |
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0-30 days: 0.8-2.2 ng/dL 1-6 months: 0.8-1.8 ng/dL 7-11 months: 0.8-1.6 ng/dL 1-6 years: 0.9-1.4 ng/dL 7-11 years: 0.9-1.6 ng/dL 12-17 years: 0.9-1.5 ng/dL 18 years and older: 0.8-1.7 ng/dL |
| CPT Code(s): | |
| 84439 |