Thyroid Stimulating Hormone
Also known as: TSH
Use
The Thyroid Stimulating Hormone (TSH) test is the preferred test for the initial screening and monitoring of thyroid function. TSH is a pituitary hormone that stimulates the thyroid gland to produce thyroxine (T4), and subsequently triiodothyronine (T3), which stimulate metabolism in almost every tissue in the body. The test measures the amount of TSH in the blood and can help in diagnosing thyroid disorders such as hypothyroidism and hyperthyroidism.
Special Instructions
The test is approved for use in New York State. When collecting specimens, use a plasma separator tube (PST) or a serum separator tube (SST). Separate serum or plasma from cells as soon as possible or within 2 hours of collection. Allow the serum specimen to clot completely at room temperature and transfer to an ARUP standard transport tube.
Limitations
The TSH test has limitations in cases such as non-thyroidal illness, pregnancy, and pituitary or hypothalamic disease, where TSH levels might not accurately reflect thyroid status. Hemolyzed specimens are unacceptable and may lead to inaccurate results. Other factors affecting TSH levels include medications, recent surgery, or acute illness. It is important to interpret TSH results in conjunction with clinical findings and other thyroid function tests.
New York Approved
Methodology
Immunoassay (ECLIA)
Biomarkers
LOINC Codes
- 3016-3
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP standard transport tube
Collection Instructions
Plasma separator tube (PST). Also acceptable: Serum separator tube (SST).
Storage Instructions
Refrigerated.
Causes for Rejection
Grossly hemolyzed specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 8 days |
| Refrigerated | 2 weeks |
| Frozen | 2 years |