The thyroid-stimulating hormone (TSH) test measures how well your thyroid gland is functioning. Your thyroid gland helps control energy, temperature, and metabolism in your body. The test checks if your thyroid gland produces the correct hormone amounts.
This article explains what your TSH test numbers mean and includes an easy-to-read chart. Understanding these numbers can clarify if your thyroid is working too fast, too slow, or just right.
How to Read TSH Results
Your TSH level tells you how actively your thyroid gland is functioning. For a comprehensive look at your thyroid function, learn more about our Complete Thyroid Panel. A high TSH number usually means your thyroid gland is underactive, also called hypothyroidism. You might notice symptoms like feeling cold, tired, gaining weight, or having dry skin.
If your TSH number is low, this usually means your thyroid gland is overactive, or hyperthyroidism. Symptoms of an overactive thyroid can include feeling hot, anxious, losing weight quickly, or having trouble sleeping. Both high and low results help identify thyroid issues clearly.
Reference Range Chart for TSH
This clear chart shows the typical TSH ranges for different people. Use this chart to quickly understand if your numbers fall within normal limits or indicate potential thyroid concerns.
| Group | Age | TSH Reference Range (mIU/L) |
|---|---|---|
| Newborns | 0 to 4 days | 1.0 – 39.0 |
| Infants | 2 weeks to 5 months | 1.7 – 9.1 |
| Children | 5 to 14 years | 0.7 – 6.4 |
| Adults (Men and Women) | 15 to 64 years | 0.4 – 4.0 |
| Seniors (65+) | 65 years and older | 0.5 – 5.0 |
| Pregnancy – 1st Trimester | First 12 weeks | 0.1 – 2.5 |
| Pregnancy – 2nd Trimester | Weeks 13 to 27 | 0.2 – 3.0 |
| Pregnancy – 3rd Trimester | Weeks 28 to birth | 0.3 – 3.5 |
According to PubMed, “the brain (pituitary gland) tells the thyroid what to do by sending out steady signals called TSH.” This helps keep the thyroid working the way it should.
TSH ranges vary based on age, gender, and special conditions like pregnancy. For example, newborn babies have much wider TSH ranges because their bodies are still adjusting outside the womb. Pregnant women also have lower TSH limits, as pregnancy hormones naturally alter thyroid function.
Older adults tend to have slightly higher TSH ranges than younger adults. Using this chart can help you spot if your TSH results fall outside typical values so you can understand more clearly what your test results indicate. Want to learn more about the TSH test? Check out our helpful, full guide to understanding TSH.
Accuracy of the TSH Test
TSH testing is highly accurate, making it very useful for diagnosing thyroid conditions. The sensitivity of the TSH blood test is around 98%. This means if you truly have a thyroid problem, the test will correctly identify it about 98% of the time.
Its specificity is approximately 92%, meaning that about 92% of healthy individuals will correctly test negative. With these high accuracy rates, you can trust your TSH test results as a dependable tool to identify potential thyroid issues clearly and reliably.
Importance Testing
TSH testing helps identify thyroid problems early. Detecting an underactive or overactive thyroid quickly allows quicker treatment, which can prevent uncomfortable symptoms from worsening. This test is especially helpful if you notice changes in your weight, mood, energy, or sleep patterns.
Regular monitoring of TSH is important if you already have a known thyroid issue. It lets you adjust medications effectively, ensuring you maintain stable thyroid hormone levels. Tracking your TSH with regular tests provides valuable insights into how effectively your thyroid treatment is working.
