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Free T4

Specimen:

Collect

  • One SST

Also Acceptable:
  • One Green Top (Li Heparin)
  • One Lavender (EDTA)
  • One Pink Top (EDTA)
  • One Red Top

Submit

  • 1 mL (Min:0.5 mL) Serum . Submit Refrigerated. Submit in a Standard Transport Tube.

Also Acceptable:
  • 1 mL (Min:0.5 mL) Plasma . Submit Refrigerated. Submit in a Standard Transport Tube.

Special Handling

  • Allow specimen to clot completely at room temperature
  • Avoid Repeated Freeze/Thaw Cycles
  • For patients receiving therapy with high biotin doses (>5 mg/day), no laboratory test specimen should be collected until at least 8 hours after the last biotin administration.
  • Separate from cells ASAP

Stability

Ambient: 2 Hour(s); Refrigerated: 7 Day(s); Frozen: 1 Month(s); Incubated: Unacceptable

Methodology

  • Electrochemiluminescence Immunoassay (ECLIA)

Performed

Mon-Fri

Reported

1-3 Day(s)

CPT Codes

  • 84439

Interpretive Data

General Reference Range : 0.71-1.70 ng/dl

Biotin in specimens taken from patients on high-dose biotin therapy or supplements may intefere with this test and cause inaccurate test results. It is recommended that for patients receiving therapy with high biotin doses (> 5 mg/day), no laboratory test specimen should be collected until at least 8 hours after the last biotin administration.

Components

  • 2146 - FREE T4
Last Updated: November 6, 2024 @ 10:13 am

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Common Test Phrases

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Common Lab Definitions

  • Serum 
  • Plasma 
  • STT