Thyroid Stimulating Hormone (TSH) with Serum/Plasma Measurement
This test measures the amount of thyroid-stimulating hormone (TSH) in your blood, which helps your thyroid gland produce hormones that regulate metabolism.
["TSH helps diagnose and monitor thyroid conditions like hypothyroidism or hyperthyroidism."]
Key facts at a glance
- LOINC
- 47952-7
- Short code
- TSH 30M p LRH IV SerPl-aCnc
- Synonyms
- TSH 30M p LRH IV SerPl-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.4
- Ref high
- 4
- Critical range
- 0.1 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84443
- SNOMED
- 301343003
- 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 healthcare provider may order this test to check for thyroid problems, such as whether your thyroid is working too slowly (hypothyroidism) or too quickly (hyperthyroidism). It’s often used as part of routine check-ups, especially in older adults or those with symptoms like fatigue, weight changes, or mood swings.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your lab uses a specific method, but this is rare for standard TSH testing. Bring any medications you’re taking, as some (like certain thyroid medications) can affect results.
What the Test Results Mean
TSH results help determine whether your thyroid is functioning normally. Low TSH may suggest hyperthyroidism, while high TSH often points to hypothyroidism. Your provider will interpret results in relation to your symptoms and medical history.
Common Conditions Linked to TSH Abnormalities
High TSH levels can indicate conditions like Hashimoto’s thyroiditis (an autoimmune disease) or primary hypothyroidism. Low TSH may signal hyperthyroidism, Graves’ disease, or pituitary issues. Always discuss results with your doctor.
Reference range
Adult: 0.4-4.0 mIU/LN/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.
TSH abnormalities can cause fatigue, weight changes, depression, or other symptoms. Regular monitoring helps manage thyroid disorders and prevent complications like heart problems or bone loss.
Short name
TSH Level
Frequently asked questions
What causes TSH levels to be too high or too low?
Can diet or lifestyle affect TSH test results?
How often should I get 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