What is a Normal TSH?

Until 2002, the official TSH "normal range" that laboratories and most doctors used throughout the U.S. was a range of 0.5 to 5.0.

On that range, a TSH under 0.5 (a low TSH) indicated hyperthyroidism (an overactive thyroid), and a TSH over 5.0 (a high TSH) indicated hypothyroidism (an underactive thyroid.)

Index: What is a Normal TSH?

1. What is a TSH Test?
2. What Does the TSH Test Measure?
3. The "Old" Normal Range
4. The "New" Normal Range
5. What the American Association of Clinical Endocrinologists Said...
6. Where Are We Now?
7. The Three Questions You Need to Ask Your Doctor
8. Where to Get More Information?