What Are Normal TSH Levels?
The Thyroid Stimulating Hormone, or TSH, is the hormone most commonly tested by physicians to check for a overactive or under active thyroid gland more commonly know as hyperthyroidism and hypothyroidism respectivley. The TSH test looks for normals TSH levels in the blood stream. Thyroid stimulating hormone is a hormonone made by your putitary gland and is responsible to regulating your body;s metobolic functions.
Now there is a consensus among the medical community as to the usefulness of TSH testing but there remains some debate as to what is considered to be a normal TSH level. Up until 2002, most medical professionals and labratories considered the range of 0.5 to 5.0 to be normal TSH levels. Anything below 0.5 was considered hypothyrodism and anything above 5.0 was considered to be hyperthyroidism. Recently however, the AACE or American Association of Clinical Endocrinolodists have set out to reccomened a new baseline criteria for normal TSH levels. These new level are .3 to 3.0.
This excerpt from a press from the AACE explain thier reasoning:
“Until November 2002, doctors had relied on a normal TSH level ranging from 0.5 to 5.0 to diagnose and treat patients with a thyroid disorder who tested outside the boundaries of that range. Now AACE encourages doctors to consider treatment for patients who test outside the boundaries of a narrower margin based on a target TSH level of 0.3 to 3.0. AACE believes the new range will result in proper diagnosis for millions of Americans who suffer from a mild thyroid disorder, but have gone untreated until now.”
“The prevalence of undiagnosed thyroid disease in the United States is shockingly high – particularly since it is a condition that is easy to diagnose and treat,” said Hossein Gharib, MD, FACE, and president of AACE. “The new TSH range from the AACE guidelines gives physicians the information they need to diagnose mild thyroid disease before it can lead to more serious effects on a patient’s health – such as elevated cholesterol, heart disease, osteoporosis, infertility, and depression.”
What is TSH testing typically used for?
Testing for Thyroid Stimulating Hormone is typically used to check the health and activity of a persons thyroid gland. Normal TSH levels indicate a healthy and properly functioning thyroid. When TSH levels are not normal it can usually be indicative of an overactive or underactive thyroid.
TSH testing is used to:
- Diagnose a thyroid disorder in a person with symptoms
- Screen adults for thyroid disorders
- In people with hypothyroidism to monitor thyroid replacement therapy
- Screen for female infertility problems
- To evaluate pituitary gland functions
- Screen newborns for an underactive thyroid
Low TSH Levels
Having low TSH test levels can indicate hyperthyroidism. Hyperthyroidism happens when the thyroid gland releases too much hormone. Hyperthyroidism can be cause by a variety of things including:
- Too much iodine in a persons system
- Viral inflammation of the thyroid gland
- Graves disease
- Taking large amounts of thyroid hormone
- Tumors on the testes or ovaries
High TSH Levels
The most common cause of hypothyroidism is inflammation of the thyroid gland. Some women develop hypothyroidism after pregnancy (often referred to as “postpartum thyroiditis”).
Other causes of hypothyroidism are:
- Congenital defects
- Radiation treatments to the neck to treat different cancers which can damage the thyroid gland
- Radioactive iodine used to treat an overactive thyroid
- Viral thyroiditis, which may cause hyperthyroidism and is often followed by temporary or permanent hypothyroidism