Quick Facts
- Sample: Blood (serum)
- Fasting: Not required
- Turn-around: 1–3 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Early detection of thyroid disorders before symptoms worsen
- Monitor thyroid medication effectiveness with accurate TSH measurements
- Convenient testing without needing a doctor's referral first
- Confidential results delivered securely to your account
- High accuracy using sensitive third-generation immunoassay technology
- Quick turnaround with results typically available within 1-3 days
Who Is This Test For?
- People experiencing unexplained fatigue, weight changes, or temperature sensitivity
- Individuals on thyroid hormone replacement therapy needing regular monitoring
- Those with family history of thyroid disease seeking preventive screening
- Women experiencing fertility issues or menstrual irregularities
- Adults seeking routine health screening for metabolic wellness
- Thyroid cancer patients requiring TSH suppression monitoring
How It Works – Just 3 Steps
- Order online – Just select your test, and place your online order
- Visit lab – Quick blood draw at any convenient location near you
- Get results – Secure online access to results within 1-3 days
FAQ
What does the TSH test measure? TSH levels in your blood, which indicate how well your thyroid gland is functioning.
Do I need to fast before this test? No fasting is required, though morning testing is preferred for most accurate results.
What medications can affect my TSH results? Biotin supplements, lithium, prednisone, and thyroid medications can alter TSH levels (Mayo Clinic 2024).
How long until I get my results? Results are typically available within 1-3 business days after sample collection.
What if my TSH results are abnormal? Abnormal results usually require follow-up testing with T3, T4, and possibly thyroid antibodies.
Can I take this test if I'm on thyroid medication? Yes, this test is commonly used to monitor thyroid hormone replacement therapy effectiveness.
More Details
What is the purpose of this test?
The TSH blood test measures thyroid-stimulating hormone levels to evaluate thyroid gland function. TSH is produced by your pituitary gland and signals your thyroid to produce hormones that control metabolism, energy use, and many vital body functions. When TSH levels are abnormal, it indicates your thyroid may be underactive (hypothyroidism) or overactive (hyperthyroidism) (American Thyroid Association 2023).
Who would benefit from this test?
This test benefits individuals with symptoms suggestive of thyroid dysfunction, including unexplained fatigue, weight changes, temperature sensitivity, or mood changes. It's particularly valuable for people on thyroid medication requiring regular monitoring, those with family history of thyroid disease, and women experiencing fertility issues. The test is also recommended for routine screening in adults over 35, especially women (CDC 2023).
When should I order a TSH test?
Consider ordering this test if you experience symptoms like persistent fatigue, unexplained weight gain or loss, feeling too hot or cold, rapid heartbeat, nervousness, or depression. It's also essential for monitoring if you're taking thyroid hormone replacement therapy. For preventive screening, testing every 5 years after age 35 is recommended, or more frequently if you have risk factors (Cleveland Clinic 2025).
How do I interpret the results?
TSH results help determine thyroid function status and guide appropriate treatment decisions.
0.4–4.0 mIU/L
- What it means: Normal thyroid function
- Typical action: No treatment needed
Above 4.0 mIU/L
- What it means: Possible hypothyroidism
- Typical action: Further testing (T4, T3)
Below 0.4 mIU/L
- What it means: Possible hyperthyroidism
- Typical action: Additional thyroid tests
Very high (>10 mIU/L)
- What it means: Likely hypothyroidism
- Typical action: Treatment usually recommended
Very low (<0.1 mIU/L)
- What it means: Likely hyperthyroidism
- Typical action: Immediate medical evaluation
Third-generation TSH assays can detect levels as low as 0.01 mIU/L, providing exceptional sensitivity for early thyroid dysfunction detection.
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.
Pre-test preparation
No fasting is required for the TSH test. However, inform your healthcare provider about all medications and supplements, as some may affect results. Biotin supplements should be stopped 3 days before testing. Schedule your test for the morning when possible, as TSH levels naturally fluctuate throughout the day (Mayo Clinic 2024).
How often should I get tested?
Testing frequency depends on your individual circumstances and thyroid health status.
- Normal results, no symptoms: Every 5 years after age 35
- Taking thyroid medication: Every 6–8 weeks initially, then every 6–12 months
- Abnormal results, untreated: Every 3–6 months
- Thyroid cancer monitoring: Every 3–6 months initially, then annually
- High-risk individuals: Annually or as recommended
Why early detection matters
Approximately 20 million Americans have thyroid disease, with many cases undiagnosed (American Thyroid Association 2023). Early detection through TSH testing prevents serious complications including cardiovascular disease, infertility, and metabolic disorders. Untreated thyroid dysfunction can significantly impact quality of life, causing persistent fatigue, mood changes, and weight problems. Prompt treatment restores normal thyroid function and prevents long-term health consequences.
Related tests you may consider
Free T4 (Thyroxine) Test – Measures actual thyroid hormone levels, providing complete thyroid function assessment when combined with TSH.
Free T3 (Triiodothyronine) Test – Evaluates active thyroid hormone levels, especially useful for diagnosing hyperthyroidism.
Thyroid Antibodies Panel – Identifies autoimmune thyroid conditions like Hashimoto's thyroiditis or Graves' disease.
