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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

FT4 | Thyroxine | SHO6650 | 1230100705

Interface Order Alias

10063

Collection Instructions

Specimen Collection: Blood

 

Container(s): Gold Top (Serum Separator-SST Gel) or Light Green Top (Lithium Heparin Gel)

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: Serum or Plasma

Centrifuge/Spin: Yes

Aliquot: Yes

Processing Instructions:

  • Serum 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 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

Age Male or Female CHW CHS
0 up to 3 days: 1.5 - 3.5 ng/dL 0.9 - 1.7 ng/dL
3 days up to 1 year: 0.9 - 2.0 ng/dL 0.9 - 1.7 ng/dL
1 year and up: 0.6 - 1.6 ng/dL 0.9 - 1.7 ng/dL

 

Performing Department

Chemistry

Performing Department Laboratory Location

CHW

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

 

CHS
Corewell Health Lakeland St. Joseph Laboratory, St. Joseph, MI
Corewell Health Lakeland Niles Laboratory, Niles, MI
Corewell Health Lakeland Watervliet Laboratory, Watervliet, 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

Updated Date

5/9/2025 - CHS info added

12/2/2025 - Gold Top Preferred specimen

Orderable Regions

Southwest; West