Published on November 14, 2016

Thyroid Function Cascade

Includes: TSH, and if indicated - FT4, T3TOT, TPO AB

Tube Type

Test ID LAB5771
EPIC Order
CPT Code(s)
84443 (additional CPT codes as indicated- see individual tests)
Group/Individual Test Group
Laboratory Core Laboratory
Tube Station Routine: 30, STAT: 888
Specimen Routine: 7 mL blood/serum separator tube/gold top/red top acceptable
3.0 mL blood/gold or red top tube (do not send microcollection devices)
Unspun: 4 hrs
Room Temp-4 hrs  (remove from gel)
Refrigerator: 7 days (remove from gel)
Frozen: 4 weeks (remove from gel)
Availability Routine: 24 hrs/day
Turnaround Time 2 hrs (for first result)
Reference Range Normal: See reference ranges for individual tests
See cascade for tests performed and ranges - Thyroid Function Cascade Flow Chart
The Thyroid Function Cascade is indicated for Non-hospitalized, asymptomatic adults without known or suspected thyroid or pituitary disease.
Thyroid Stimulating Hormone is tested initially. Based on the result, a Free T4 and/or Total T3 and/or Thyroid Peroxidase Antibody will be reflexed.

Reviewed by jcayless on December 28, 2021

Note: Reference ranges provided on this web site are for guidance only, and may not reflect the most recent changes. Refer to laboratory reports for current reference data.

UNC Hospitals
McLendon Clinical Laboratories
101 Manning Drive
Chapel Hill, NC 27514