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Test Code T3UP T3 (Triiodothyronine), Uptake, Serum

Performing Laboratory

Northwell Health Laboratories



Includes calculation of free thyroxine (T4) index when T4 is also ordered.

Reference Values

% T3UP: 28-41%

Index: 0.80-1.30

FTI%: 1.3-4.9%

Test Classification and CPT Coding


Specimen Required

Container/Tube: Gold-top tube(s)

Specimen: 1 mL of serum

Transport Temperature: Refrigerate

Day(s) and Time(s) Performed

Monday through Sunday

Computer Interface Code

PDM #  5300420