Thyroid-stimulating hormone (TSH) concentration in serum/plasma
This test measures the level of thyroid-stimulating hormone in your blood, which helps your thyroid gland produce hormones that regulate metabolism, energy, and growth.
["TSH helps diagnose thyroid disorders and monitor treatment for conditions like hypothyroidism or hyperthyroidism."]
Key facts at a glance
- LOINC
- 90301-3
- Short code
- T gondii Amn Ql Cult
- Synonyms
- T gondii Amn Ql Cult
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- organism-specific-culture
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a TSH test to check for thyroid problems, such as underactive (hypothyroidism) or overactive (hyperthyroidism) thyroid function. It’s often the first test used to screen for these conditions, especially if you have symptoms like fatigue, weight changes, or sensitivity to heat/cold.
When Might You Need This Test?
You might need this test if you have symptoms like unexplained weight changes, fatigue, depression, or changes in your menstrual cycle. It’s also used during pregnancy, to monitor thyroid hormone replacement therapy, or if you have a family history of thyroid disease.
What to Expect Before the Test
No special preparation is usually needed, but your doctor might ask you to stop certain medications (like thyroid hormone replacement) for a short time before testing. Drink plenty of water the day of the test to help with blood flow.
What Happens During the Test?
A healthcare provider will draw blood from a vein in your arm. The blood sample is sent to a lab for analysis. The process takes about 15 minutes, and you may feel slight discomfort, but it’s generally quick and painless.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A TSH test is critical for diagnosing thyroid disorders. Low TSH levels often indicate hypothyroidism (underactive thyroid), while high TSH levels may suggest hyperthyroidism (overactive thyroid) or other conditions like pituitary problems. It’s also useful for monitoring thyroid hormone replacement therapy to ensure levels are stable and effective.
Short name
TSH (Serum/Plasma)
Frequently asked questions
How long does it take to get my TSH test results?
Can I eat or drink anything before my TSH test?
What are common symptoms of thyroid problems that might lead to a TSH test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy