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.
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.

Compliance Category

FDA

Note

T3 uptake is of little clinical value alone; it is used to determine the Free Thyroxine Index.

Hotline History
N/A
CPT Codes

84479

Components
Component Test Code* Component Chart Name LOINC
0070135 T3 Uptake 3050-2
* 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
T3 Uptake