Triiodothyronine (T3), Free by Equilibrium Dialysis/LC-MS/MS

Also known as: T3 FREE SP

Clinical Use

Use

The Triiodothyronine (T3), Free by Equilibrium Dialysis/LC-MS/MS test is used to measure the levels of free triiodothyronine in the blood, which is a critical parameter in evaluating thyroid function. T3 is one of the two primary hormones produced by the thyroid gland, and its free form is the biologically active form, making its measurement crucial for diagnosing and managing thyroid disorders. This test aids in the differential diagnosis of hyperthyroidism and monitoring thyroid status, especially in individuals with altered thyroid-binding protein levels or conditions affecting hormone distribution such as pregnancy.

Special Instructions

Not provided.

Limitations

This test is performed using a non-FDA approved method developed by a commercial laboratory and is not validated for clinical use by the FDA. It may not be suitable for diagnosing certain thyroid disorders due to potential variability introduced by different laboratory methods. Interference with the equilibrium dialysis step or mass spectrometry measurement could result in inaccurate free T3 levels. Factors such as sample contamination, improper handling, or suboptimal pre-analytical conditions could also affect test outcomes. Therefore, clinical correlation with other thyroid function tests and patient presentation is necessary.

Test Details

New York Approved

Methodology

Mass Spectrometry

Biomarkers

LOINC Codes

Order Codes

29239-1 - T3Free SerPl Dialy-mCnc

Result Turnaround Time

8-14 days

Specimen

Plasma

Volume

1 mL

Minimum Volume

0.3 mL

Container

ARUP standard transport tube

Collection Instructions

Separate from cells ASAP or within 45 minutes of collection. Use plain red or lavender (K2EDTA), SST, lavender (K3EDTA), pink (K2EDTA), plasma preparation tube (PPT), or green (sodium heparin) for collection.