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Epic Code LAB127 T4 (Thyroxine), Free

Important Note

Method is Roche cobas Electrochemiluminescense Immunoassay.
Patient results determined by assays using different manufacturers for methods may not be comparable.

Test Name Alias

Free T4 Level | FT4 | T4 free | Thyroxine | T4 | 6650

Interface Order Alias

10063

Collection Instructions

Specimen Collection: Blood

 

Container(s): 4.5 mL Mint Green Top (Lithium Heparin Gel) or 5.0 mL Gold Top (Serum Separator-SST Gel)

Preferred Volume to Collect: 4.5 mL

Minimum Volume to Collect: 1.0 mL

Neonate Volume to Collect: 0.5 mL

Capillary collect ok? Yes

Microtainer acceptable: Yes

 

Collection Instructions:

  • After collection, gently invert tube 8-10 times.
  • Specimen should be processed within 2 hours – See Processing Instructions.

 

 

Processing Instructions (Laboratory, Outpatient or Off-site collection)

 

Processed Specimen: Plasma or Serum

Centrifuge/Spin: Yes

Aliquot: Yes

Processing Instructions:

  • Plasma is preferred specimen type
  • Green Tube/Plasma: Centrifuge after collection.
  • Gold Tube/Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.

Transport Temperature: Refrigerate

Specimen Stability

Ambient: 8 hours

Refrigerate: 72 hours

Frozen: aliquot plasma/serum for longer storage

Laboratory Retention: 72 hours

Test Frequency

Available daily, usual TAT 1 day.

Reference Range

0 up to 3 days: 1.5 - 3.5 ng/dL

3 days up to 1 year: 0.9 - 2.0 ng/dL

1 year and up: 0.6 - 1.6 ng/dL

Performing Department

Chemistry

Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI
Corewell Health Big Rapids Laboratory, Big Rapids, MI
Corewell Health Gerber Laboratory, Fremont, MI
Corewell Health Kelsey Laboratory, Lakeview, MI
Corewell Health Ludington Laboratory, Ludington, MI
Corewell Health Pennock Laboratory, Hastings, MI
Corewell Health Reed City Laboratory, Reed City, MI
Corewell Health Greenville Laboratory, Greenville, MI
Corewell Health Zeeland Laboratory, Zeeland, MI

Methodology

Method is Roche cobas Electrochemiluminescense Immunoassay.
Patient results determined by assays using different manufacturers for methods may not be comparable.

CPT

84439

CDM Code

3018443901

Epic Test ID

1230100705

LOINC

Free T4: 3024-7

Mayo Access Code

SHO6650

Reviewed Date

3/7/2024