Test Center

My Recent Searches

  • No Recent Search.

My Tests Viewed

  • No Test Viewed.
  • Ordering Info

T3 Free, Tracer Dialysis

Test Code


CPT Code(s)

84480, 84481


Free T3, T3 Total

Preferred Specimen(s)

1 mL serum

Minimum Volume

0.5 mL

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days


Equilibrium Dialysis • Immunochemiluminometric Assay (ICMA)

This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Performing Laboratory

Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130

Setup Schedule

Set up: Sun-Thurs; Report available: 4-7 days

Reference Range(s)

Free T3

 1-9 Years 282-518 pg/dL 
 10-13 Years 286-556 pg/dL
 14-17 Years 252-501 pg/dL
 Adult 210-440 pg/dL
 Pregnancy (all trimesters) 200-380 pg/dL 
T3 Total
<1 Month Not established
1-23 Months 117-239 ng/dL
2-12 Years 105-207 ng/dL
13-20 Years 86-192 ng/dL
>20 Years 76-181 ng/dL

Clinical Significance

T3 measurements are used to diagnose hyperthyroidism. This test can also be used to clarify thyroid status in the presence of possible protein-binding abnormalities.

Alternative Name(s)

Triiodothyronine, Free T3

LOINC®' Code(s)

The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.

NOTE: The codes listed in the table below are not orderable Test Codes.

Result NameLOINC CodeComponent Name
55080300T3, TotalPending assignment
85990760Free T3Pending assignment

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided 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 payer being billed.

LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.

* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.