Thyroid Function Interpreter — TSH, T3, T4 Results
Enter your TSH, Free T4, and Free T3 lab test results to get a plain-English clinical interpretation of your thyroid hormone status.
Understanding Thyroid Function Tests
The thyroid gland is a butterfly-shaped endocrine organ in the neck that regulates metabolism, body temperature, energy expenditure, and heart rate. A thyroid panel typically measures Thyroid Stimulating Hormone (TSH), Free Thyroxine (FT4), and Free Triiodothyronine (FT3).
The Feedback Loop
Thyroid function is controlled by a feedback loop between the pituitary gland and the thyroid. Pituitary-secreted TSH stimulates the thyroid to produce T4 and T3. When thyroid hormones are abundant, TSH production drops; when they are scarce, TSH rises. Thus, a high TSH typically signals an underactive thyroid, while a low TSH signals an overactive one.
Common Patterns Interpreted
- Hypothyroidism: Elevated TSH and low Free T4. Symptoms include fatigue, weight gain, and cold intolerance.
- Hyperthyroidism: Suppressed TSH and elevated Free T4/FT3. Symptoms include rapid heart rate, weight loss, and anxiety.
- Subclinical Status: Abnormal TSH with normal hormone levels, representing early or mild dysfunction.