T-Uptake
Test Code
TUP
Description
The T3, Free (FT3) test measures serum triiodothyronine (T3) not bound to thyroid hormone-binding proteins (thyroid hormone-binding globulin [TBG], transthyretin, albumin). It is used, primarily in concert with measurement of thyroid-stimulating hormone.
Collect
Plain red top or SST tube.
Pediatric Collection
Minimum volume: 0.3mL serum
Unacceptable Conditions
Grossly hemolyzed specimens, more than one freeze/thaw cycle.
Storage Transport Temp
Offsite: Frozen. Send serum Priority Overnight via FedEx and in a well insulated container on dry ice.
Stability
8 hours room temperature
48 hours refrigerated at 2-8°C
>48 hour frozen at -20°C
Performed
Mon-Fri
Methodology
1 Step Competitive Chemiluminescent
Turnaround Time
Results same day if samples are received prior to 6PM
Department
Core Lab
Synonyms
Triiodothyronine Uptake (T3 Uptake);TUPTX
Study Offerings
Not offered
Reference Interval
32.0 - 48.4% Uptake
CPT Code
84479
New York Approved
FDA Approved or Cleared
FDA
Approved or Cleared