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T3 Uptake
0070135
Ordering Recommendation

Not recommended for routine thyroid screening.

Mnemonic
T3 UP
Methodology
Quantitative Electrochemiluminescent Immunoassay
Performed
Sun-Sat
Reported
Within 24 hours
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum Separator Tube (SST). Also acceptable: Plasma Separator Tube (PST), Lavender (EDTA), Pink (K2EDTA), or Green (Sodium or Lithium Heparin). 
Specimen Preparation
Allow specimen to clot completely at room temperature. Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum or plasma to an ARUP Standard Transport Tube. (Min: 0.5 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Grossly hemolyzed specimens. 
Remarks
 
Stability
After separation of cells: Ambient: 8 days; Refrigerated: 2 weeks; Frozen: 2 years 
Reference Interval
28-41% uptake
Interpretive Data
Thyroxine, Free (Free T4) (0070138) is the preferred test alternative for T3 uptake and Free Thyroxine Index tests.

Note
T3 uptake is of little clinical value alone; it is used to determine the Free Thyroxine Index.
Hotline History
N/A
Components
Component Test Code*Component Chart NameLOINC
0070135T3 Uptake3050-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • T-Uptake
  • T3 Uptake, S
  • T3U, Serum
  • THBR
  • Thyroid Binding Ratio
  • Triiodothyronine Uptake, Serum