GGT (Gamma-Glutamyl Transferase): What Your Results Mean
Bottom line: GGT is a liver and bile duct enzyme. Normal is 0-45 U/L. High GGT often indicates liver stress or alcohol use.
What Is TSH (Thyroid Stimulating Hormone)?
TSH (thyroid stimulating hormone) is produced by the pituitary gland and tells your thyroid how much thyroid hormone to make. It is the most sensitive screening test for thyroid disorders.
When your thyroid is underactive (hypothyroidism), TSH rises as the pituitary tries to stimulate more hormone production. When the thyroid is overactive (hyperthyroidism), TSH drops because the pituitary senses excess thyroid hormone and stops stimulating production.
Thyroid disorders affect roughly 20 million Americans, and up to 60% of those with thyroid disease are unaware of their condition. TSH testing is the primary way to detect these often-silent conditions.
TSH (Thyroid Stimulating Hormone) Reference Ranges
| Classification | Range (mIU/L) |
|---|---|
| Very Low (Possible Hyperthyroidism) | Below 1.09 |
| Low (Suppressed) | 0.1 - 0.44 |
| Normal | 0.45 - 4.5 |
| Mildly Elevated (Subclinical Hypothyroidism) | 4.6 - 10.0 |
| High (Hypothyroidism) | 10.1 - 20.0 |
| Very High | 20.1 - 100.0 |
What Affects Your TSH (Thyroid Stimulating Hormone) Levels?
- Autoimmune conditions (Hashimoto's, Graves' disease)
- Iodine intake (deficiency or excess)
- Medications including lithium, amiodarone, and thyroid medications
- Pregnancy (normal ranges shift)
- Age (TSH tends to increase with age)
- Recent illness or stress
When to Get Tested
Adults should consider TSH screening starting at age 35, then every 5 years. Earlier and more frequent testing if you have symptoms (fatigue, weight changes, cold intolerance, hair loss) or a family history of thyroid disease.
Look Up Your TSH (Thyroid Stimulating Hormone) Result
Select your value below to see a detailed breakdown of what it means:
Low (Suppressed)
Normal
Mildly Elevated (Subclinical Hypothyroidism)
High (Hypothyroidism)
Read the Full Blood Test Guide
Frequently Asked Questions
The standard normal range is 0.4-4.0 mIU/L, though some experts argue the upper limit should be closer to 2.5 mIU/L. The optimal range depends on age, pregnancy status, and individual health history.
High TSH usually indicates hypothyroidism, an underactive thyroid. The pituitary is producing more TSH to try to stimulate a sluggish thyroid. Common symptoms include fatigue, weight gain, cold sensitivity, and dry skin.
Acute stress can temporarily suppress TSH levels. Chronic stress may also affect thyroid function indirectly. For the most accurate reading, test during a period of relative stability.