Understanding TSH Levels

TSH Levels is a measure used to identify Thyroid level in human body. TSH full form is 'Thyroid Stimulating Hormone' and it is a blood test used to figure out if there is a thyroid gland problem or not.

TSH Levels and Thyroid

TSH or Thyroid Stimulating Hormone is important for proper functioning of Thyroid. It allows generation of two by-product hormones - triiodothyronine (T3) and thyroxine (T4). T3 and T4 both control our body basic metabolic function and are important for normal growth of brain (especially in new born).

TSH levels can be either - 1) Normal Level, 2) High Level, 3) Low Level

Normal TSH Level

  • Adult (21 to 54 years) - 0.4-4.2 microunits per milliliter (mcU/mL) or 0.4-4.2 milliunits per liter (mU/L)
  • Adult (55‑87 years) - 0.5‑8.9 mIU/L
  • Children (1 to 4 days): 1-39 mcU/mL or 1-39 mU/L
  • Children (2‑20 weeks): 1.7‑9.1 mIU/L
  • Children (21 weeks to 20 years): 0.7-6.4 mcU/mL or 0.7-6.4 mU/L

High TSH Level**

Any reading above the normal TSH level is considered high. For example. in adults (21 - 54 year), a level of above 4.2 is considered high.

High TSH levels means your thyroid gland is under active and is producing too little T2 and T3 hormones. Hence to increase the production of T2 and T3, body automatically increases TSH hormone in the body. Medically this is known as 'Hypothyroidism'

Low TSH Level**

Any reading below the normal level is considered low. For example, in adults (21 - 54 year), a level below 0.4 is considered low.

Low TSH levels means your thyroid gland is over active and producing too much T2 and T3 hormones. To compensate that, body is producing too little TSH hormone. Medically this is called 'Hyperthyroidism'