Normal thyroid stimulating hormone (TSH) levels vary depending on a person's age and stage of physical growth. Infants and children have higher TSH levels than adults and adolescents. Abnormal TSH levels may indicate a current or potential unhealthy thyroid condition.
Thyroid stimulating hormone levels are measured to test the overall function of the thyroid, a gland that controls metabolism and hormone regulation in the body.
Abnormal TSH Levels
High TSH levels may indicate a condition known as hyperthyroidism (overactive thyroid), while low TSH levels may indicate a hypothyroid condition (underactive thyroid).
Normal TSH Levels in Adolescents and Adults
The normal TSH level for adults and adolescents who have reached puberty have is between 0.5 to 4.8 units per millilitre (uU/ml) of blood serum.
Normal TSH Levels in Children
Children who have not yet reached puberty have TSH levels of between 0.6 to 5.5 uU/ml of blood serum.
Normal TSH Levels in Infants
Full-term infants at four days of age have normal TSH levels of between 1.3 and 16 uU/ml of blood serum; at one to eleven months of age, full-term infants have normal TSH levels of between 0.9 and 7.7 uU/ml of blood serum.