T3 Uptake (T3U)

Test Code

Quest Code

Alias/See Also

CPT Codes

Preferred Specimen
1 mL serum in gold top tube

Minimum Volume
0.5 mL

Other Acceptable Specimens
Plain red top tube

Transport Container
Transport tube

Transport Temperature
Room temperature

Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days

Immunoassay (IA)

Setup Schedule
AM Monday-saturday

Report Available
3 days

Reference Range
See Laboratory Report

Clinical Significance
T3 uptake (T3U) is used with measurement of thyroxine (T4) to calculate the free T4 index. The calculated free T4 is useful in the assessment of thyroid diseases. Elevations are associated with hyperthyroidism or thyroid hormone resistance whereas low concentrations are associated with hypothyroidism.

Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.