Triiodothyronine, Total (Total T3)
Also known as: T3 TOTAL
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.
New York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 3053-6
- 3053-6
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
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.
Storage Instructions
Refrigerated
Causes for Rejection
Grossly hemolyzed specimens
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 8 days |
| Refrigerated | 2 weeks |
| Frozen | 1 year |