Thyroid Stimulating Hormone (TSH) with Triple Stimulation Test via Oral Bolus (Serum/Plasma)
This test measures how your thyroid gland responds to different doses of thyroid hormone-stimulating medication. It helps assess whether your thyroid is functioning normally or if it may be underactive (hypothyroidism).
["This test evaluates your thyroid’s sensitivity to medication and helps diagnose potential thyroid issues."]
Key facts at a glance
- LOINC
- 40399-8
- Short code
- TSH 20M p Triple Bolus SerPl-aCnc
- Synonyms
- TSH 20M p Triple Bolus 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
- 85610
- SNOMED
- 396252006
- 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 this test if you have symptoms of thyroid problems, such as fatigue, weight changes, or unexplained mood swings. It may also be used to monitor thyroid function in people with known thyroid disorders or those taking thyroid replacement medication.
How the Test Works
You’ll take three doses of a synthetic thyroid hormone (levothyroxine) over several days. Blood samples are drawn before and after each dose to measure your TSH levels. This helps determine how your body responds to the medication.
What to Expect Before the Test
No special preparation is needed, but inform your doctor about any medications, including thyroid supplements, you’re taking. Avoid smoking or caffeine before testing, as they can affect hormone levels.
What to Expect During the Test
Blood samples are taken from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. The test itself is quick, but you may need to stay for a short time to allow the blood to clot or separate.
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.
Abnormal results may indicate thyroid resistance to medication, which can happen in conditions like hypothalamic-pituitary dysfunction or rare genetic disorders. High TSH levels after stimulation could suggest your body isn’t responding well to treatment, while low levels might indicate overstimulation or other thyroid-related issues.
Short name
Triple Stimulation TSH Test
Frequently asked questions
How long does the test take to get results?
Will I need to take any special steps after the test?
Can I drink alcohol 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 16, 2026. · Read our editorial policy