Thyroid Stimulating Hormone (TSH) with High-Performance Liquid Chromatography (HPLC) and Immunoassay Confirmation
This test measures the level of thyroid-stimulating hormone (TSH) in your blood, which helps your thyroid gland produce hormones. It’s often used to check for thyroid function, including conditions like hypothyroidism or hyperthyroidism.
["TSH levels help diagnose and monitor thyroid disorders by signaling how well your thyroid is working."]
Key facts at a glance
- LOINC
- 47947-7
- Short code
- TSH 1.5h p LRH IV SerPl-aCnc
- Synonyms
- TSH 1.5h 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 doctor may order this test if you have symptoms like fatigue, weight changes, or unexplained mood swings. It’s also used to screen for thyroid issues before surgery, during pregnancy, or if you have family history of thyroid problems. Sometimes, it’s part of routine check-ups for adults over 50.
How the Test Works
A blood sample is taken from a vein in your arm. The sample is processed to separate serum/plasma, where TSH levels are measured using two methods: HPLC for initial screening and immunoassay for confirmation. This ensures accurate detection of even small changes in hormone levels.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if instructed by your doctor. Wear comfortable clothing and bring any medications you’re currently taking, as some may affect results.
What to Expect During the Test
The test takes about 15–30 minutes. A healthcare provider will insert a small needle into your arm to draw blood. You may feel a slight pinch, but it’s usually over quickly. The blood is then sent to a lab for analysis.
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.
Low TSH levels may indicate hyperthyroidism (overactive thyroid), while high TSH levels often suggest hypothyroidism (underactive thyroid). Abnormal results can guide treatment, such as medication adjustments or further testing for conditions like thyroid nodules or autoimmune diseases.
Short name
TSH with HPLC/Immunoassay
Frequently asked questions
What does a high TSH level mean?
What does a low TSH level mean?
Can diet affect TSH test results?
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