Quick Facts
- Sample: Blood
- Fasting: No fasting required (stop biotin at least 72 hours before collection)
- Turnaround: 1-3 days (may take longer due to weather, holidays, or lab delays)
What This Test Measures
This test measures thyroid-stimulating hormone (TSH), also known as thyrotropin, in your blood. TSH is produced by the pituitary gland, not the thyroid itself. It rises when thyroid hormone levels are low and falls when thyroid hormone levels are high, so it reflects how your pituitary gland is responding to your thyroid's output.
Because TSH is the body's main regulator of thyroid activity, measuring it gives your healthcare provider a direct look at thyroid function. This test reports a single quantitative TSH value. It does not measure T3, T4, thyroid antibodies, or any other thyroid-related analyte.
Benefits
- Provides a direct measure of thyroid function through TSH levels
- Helps identify signs of an overactive or underactive thyroid
- Supports monitoring of thyroid hormone replacement therapy
- Assists in evaluating female infertility concerns
- Helps assess pituitary gland function
Who Is This Test For?
- Adults with symptoms of hyperthyroidism, such as unexplained weight loss or a fast heart rate
- Adults with symptoms of hypothyroidism, such as fatigue or unexplained weight gain
- People currently on thyroid hormone replacement therapy who need monitoring
- Individuals working with a provider on female infertility evaluation
- Individuals whose provider wants to evaluate pituitary gland function
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this thyroid test?
This test measures thyroid-stimulating hormone (TSH), a hormone made by the pituitary gland that regulates thyroid activity. It helps a healthcare provider evaluate whether your thyroid is producing an appropriate amount of hormone. Because TSH rises and falls in response to thyroid hormone levels, this test provides direct information about thyroid function. It is not a panel and does not measure additional thyroid hormones or antibodies.
2. Who would benefit from this test?
This test may be useful for adults with symptoms of an overactive or underactive thyroid, people being monitored on thyroid hormone replacement therapy, individuals evaluating female infertility concerns with their provider, and those whose provider wants to check pituitary gland function. A healthcare provider can help determine if this test fits your situation.
3. When should I order this test?
You may consider this test if you are experiencing symptoms associated with too much or too little thyroid hormone, if your provider is monitoring your thyroid hormone replacement therapy, or if you are working through an infertility evaluation. This test does not replace a full medical evaluation, and opinions differ on general screening recommendations, so it's best discussed with your provider.
4. How does this test differ from other thyroid tests?
This test measures TSH specifically, which is produced by the pituitary gland to regulate thyroid activity. It differs from tests that measure thyroid hormones themselves (such as T3 or T4), thyroid antibodies, or thyroid-binding proteins. TSH testing offers a different piece of information than these other tests, and results are often reviewed together for a fuller picture of thyroid health.
5. Do I need to fast before this test?
No fasting is required for this test. However, you should stop biotin consumption at least 72 hours prior to your blood collection, as biotin can interfere with test results.
6. How quickly will I get results?
Results are typically available in 1-3 days. This may take longer depending on weather, holidays, or other lab delays.
7. How do I interpret the results?
The meaning of your TSH result depends on your symptoms, medical history, medications, supplements, and other lab results your provider may review alongside it. TSH results are often interpreted together with other thyroid measurements when appropriate. One abnormal TSH result does not automatically confirm a thyroid condition, and one normal result does not automatically rule one out. Your healthcare provider is best positioned to interpret your results in context.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
8. What should I do if my results are abnormal?
If your results fall outside the expected range, review them with a qualified healthcare provider. They can help determine what the result means for you and whether any additional evaluation or testing is appropriate. This test result on its own does not provide a complete clinical conclusion.
9. How often should I get tested?
How often you should be tested depends on your individual health situation. Follow the testing schedule recommended by your healthcare provider, as directed by your healthcare provider.
Pre-test preparation
No fasting is required for this test. Stop biotin consumption at least 72 hours prior to your blood collection.
