Lab Tests for Hypothyroidism
Hypothyroidism occurs when your thyroid gland doesn't produce enough thyroid hormones, slowing your metabolism and affecting energy, weight, and mood. Regular lab monitoring is essential for diagnosing hypothyroidism, adjusting medication dosages, and tracking your thyroid function over time. With JustLabs, you can order hypothyroidism blood tests directly — no doctor visit or insurance required. Results are available in your account within 1-2 business days after your blood draw at any Quest Diagnostics location.
Recommended Tests
Understanding Your Results
| Test | Normal Range | Low Means | High Means |
|---|---|---|---|
| TSH | 0.4–4.0 mIU/L | Possible hyperthyroidism or over-medication | Underactive thyroid (hypothyroidism) |
| Free T4 | 0.8–1.8 ng/dL | Thyroid not producing enough hormone | Excess thyroid hormone production |
| Free T3 | 2.3–4.2 pg/mL | Poor T4-to-T3 conversion | Overactive thyroid or supplementation |
| TPO Antibodies | <35 IU/mL | Normal — no autoimmune thyroid attack | Hashimoto's thyroiditis likely |
| Reverse T3 | 9.2–24.1 ng/dL | Rarely clinically significant | Stress, illness, or conversion issue |
How to Order
Order Online
Select your tests and pay securely. A licensed physician authorizes your order.
Visit Quest Diagnostics
Walk into any of 2,200+ Quest locations nationwide. No appointment needed.
Get Results
Results available in your account within 1-2 business days.
Frequently Asked Questions
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Content reviewed for accuracy by the JustLabs editorial team.