Triiodothyronine, Total (Total T3)

Casandra

Casandra Test Code AR05190Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 0070474CPT Code 84480

Triiodothyronine, Total (Total T3)

Also known as: T3 TOTAL

Clinical Use

Order Test

Use

The Triiodothyronine, Total (Total T3) test is a quantitative assay used in the evaluation of thyroid function. It is primarily used to assist in the diagnosis of thyrotoxicosis and hyperthyroidism, conditions characterized by excessive thyroid hormone levels. Total T3 measurement can be valuable in initial thyroid disorder evaluations, supplementing Thyroid Stimulating Hormone (TSH) assessments to provide a more comprehensive picture of thyroid health.

Special Instructions

This test is not recommended for routine thyroid screening. For initial thyroid disorder assessment, the Thyroid Stimulating Hormone (TSH) test is preferred. Serum should be separated from cells as soon as possible, ideally within 2 hours of collection. Use ARUP standard transport tubes for transferring serum or plasma.

Limitations

Test results might be influenced by variables such as sample handling and the presence of anti-T3 antibodies in the blood. Additionally, factors like consumption of certain medications or supplements might affect the accuracy of the test, necessitating careful consideration of patient history. Grossly hemolyzed specimens are unacceptable as they might lead to inaccurate T3 quantification.

Test Details

New York Approved

Methodology

Immunoassay (ECLIA)

Biomarkers

Triiodothyronine, Total

Analyte

T3 Total Level • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

3053-6

Result Codes

3053-6

Result Turnaround Time

1 day

Specimen

Serum

Volume

1 mL

Minimum Volume

0.5 mL

Container

ARUP standard transport tube

Collection Instructions

Collect specimen in a serum separator tube (SST). Other acceptable containers include Lavender (K2 EDTA or K3 EDTA), pink (K2 EDTA), or green (lithium heparin) tubes. Allow specimen to clot completely at room temperature before separating serum.