Thyroid Stimulating Hormone (TSH) with Serum/Plasma Retrospective Analysis
This test measures your thyroid-stimulating hormone level, which helps your body regulate thyroid hormone production. It’s often used to check for thyroid function, including conditions like hypothyroidism or hyperthyroidism.
["Your TSH levels help doctors diagnose and monitor thyroid disorders."]
Key facts at a glance
- LOINC
- 33269-2
- Short code
- TSH pre TRH SerPl-aCnc
- Synonyms
- TSH pre TRH 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
A TSH test is commonly ordered to evaluate thyroid function. It may be part of a routine checkup, especially if you have symptoms like fatigue, weight changes, or unexplained issues with metabolism. Doctors may also order it if you have a family history of thyroid problems or if you’ve been diagnosed with conditions like Hashimoto’s disease or Graves’ disease.
What to Expect Before the Test
No special preparation is needed for this test. You may have a blood sample drawn from a vein in your arm, similar to other blood tests. If this is a retrospective analysis, your blood sample may have been stored for later testing.
What the Test Results Mean
TSH levels can vary based on your thyroid health. High levels may suggest hypothyroidism (underactive thyroid), while low levels may indicate hyperthyroidism (overactive thyroid). Your doctor will interpret results in relation to your symptoms and medical history.
Common Conditions This Test Helps Diagnose
This test is critical in diagnosing and managing thyroid disorders, such as hypothyroidism (e.g., Hashimoto’s thyroiditis), hyperthyroidism (e.g., Graves’ disease), or thyroid nodules. It can also help monitor treatment effectiveness for thyroid hormone replacement.
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.
◆Associated findings1
Short name
TSH (Retrospective)
Frequently asked questions
What does a retrospective TSH test mean for me?
Will I need to do anything differently if this is a retrospective test?
How long will it take to get my 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