Thyroid Stimulating Hormone (TSH) with Serum/Plasma Specimen
This test measures the amount of thyroid-stimulating hormone (TSH) in your blood. TSH helps regulate your thyroid hormone levels, which control metabolism, energy, and other bodily functions.
["TSH helps doctors check if your thyroid is working properly."]
Key facts at a glance
- LOINC
- 47192-0
- Short code
- T3 sp3 p chal SerPl-sCnc
- Synonyms
- T3 sp3 p chal SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 80
- Ref high
- 200
- Critical range
- 20 N/A – 400 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84436
- SNOMED
- 302346007
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order a TSH test to evaluate thyroid function, diagnose thyroid disorders (such as hypothyroidism or hyperthyroidism), or monitor thyroid treatment. It’s often the first test used to check thyroid health because it’s sensitive and reflects thyroid hormone levels accurately.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm or hand to draw blood. If you’re on thyroid medication, let your doctor know beforehand, as it may affect results.
What the Test Results Mean
TSH levels can vary based on your health, age, and other factors. High TSH levels may suggest hypothyroidism (underactive thyroid), while low levels may indicate hyperthyroidism (overactive thyroid). Your doctor will interpret results in the context of your symptoms and medical history.
Common Conditions Linked to TSH Results
Abnormal TSH levels can signal conditions like thyroid nodules, pituitary disorders, or autoimmune diseases (e.g., Hashimoto’s disease or Graves’ disease). Regular monitoring may be needed if you have a history of thyroid issues or take thyroid medication.
Reference range
Adult: 80-200 ng/dLN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
TSH Level
Frequently asked questions
Will fasting affect my TSH test results?
How long will I need to wait for my results?
Can I take my thyroid medication before the 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 17, 2026. · Read our editorial policy