TSH Meaning
TSH stands for Thyroid Stimulating Hormone and is a substance produced in the brain, specifically in the pituitary gland. This substance stimulates the thyroid gland to produce thyroid hormone, T3 and T4. The release of TSH is regulated by the amount of thyroid hormone present via a negative feedback system. If there is enough thyroid hormone, and the thyroid gland is working optimally, then TSH is normal. If there is too little thyroid hormone, and thus the thyroid is working too slowly, then TSH is often elevated. Conversely, if there is too much thyroid hormone and the thyroid gland is working too fast, then there is often a decreased TSH.
To determine thyroid function, it is best to measure the biomarkers TSH and T4.
TSH Values in Men and Women: Detailed Explanation
Here is an overview of TSH levels in men and women so you can see when your TSH level is normal, low or high.
Normal:
A TSH level between 0.29 and 3.99 mU/L is considered normal. This indicates a healthy balance of thyroid function.
Low:
When the TSH level is below 0.27 mU/L, it is considered abnormal and too low. This may indicate an overactive thyroid (hyperthyroidism) and should be investigated further in conjunction with the fT4 value. Values between 0.27 and 0.29 mU/L are considered “elevated,” meaning the TSH level is at the lower limit of normal.
High:
A TSH value above 3.99 mU/L is on the high side of normal. Values between 3.99 and 4.2 mU/L are considered “elevated,” indicating that the TSH level is at the upper limit of normal. If the value exceeds 4.2 mU/L, it is considered abnormal and too high, which may indicate a slow thyroid gland (hypothyroidism). Further interpretation is then required in conjunction with the fT4 value.
Invalid:
A value of 0 mU/L is considered invalid, possibly due to insufficient material for the test. A new measurement is recommended.
TSH Values in Men et Woman: Detailed Explanation
| Result | Unit | Value min-max | Age | Gender | Biomarker interpretation |
|---|---|---|---|---|---|
| Deviant | mU/L | 0 - 0.27 | 18 - 100 | Man & Woman | The TSH falls outside the normal range and is too low. Interpretation depends on the thyroid hormone fT4. |
| Caution | mU/L | 0.27 - 0.29 | 18 - 100 | Man & Woman | The TSH is still within the normal range, but on the low side. |
| Normal | mU/L | 0.29 - 3.99 | 18 - 100 | Man & Woman | The TSH is good. |
| Caution | mU/L | 3.99 - 4.2 | 18 - 100 | Man & Woman | The TSH is still within the normal range, but on the high side. |
| Deviant | mU/L | 4.2 - 50 | 18 - 100 | Man & Woman | The TSH falls outside the normal range and is too high. Interpretation depends on the thyroid hormone fT4. |
