What to Check for Thyroid in Blood Work
The thyroid gland, located in the neck, plays a crucial role in regulating metabolism, growth, and development in the body. To ensure the thyroid is functioning properly, doctors often recommend blood tests to measure various thyroid hormones. In this article, we will discuss the key parameters to check for thyroid health in blood work.
1. Thyroid-Stimulating Hormone (TSH)
Thyroid-Stimulating Hormone (TSH) is the primary hormone measured in thyroid blood tests. It is produced by the pituitary gland and stimulates the thyroid to produce thyroid hormones. The normal range for TSH varies depending on the laboratory, but generally, it falls between 0.4 to 4.0 mIU/L. Elevated TSH levels may indicate hypothyroidism, where the thyroid gland is underactive. Conversely, low TSH levels can suggest hyperthyroidism, where the thyroid gland is overactive.
2. Free Thyroxine (FT4)
Free Thyroxine (FT4) is the active form of thyroid hormone that binds to the thyroid hormone receptors in the body. It is crucial for regulating metabolism. The normal range for FT4 is typically between 0.8 to 1.8 ng/dL. High levels of FT4 may indicate hyperthyroidism, while low levels can suggest hypothyroidism.
3. Free Triiodothyronine (FT3)
Free Triiodothyronine (FT3) is another active thyroid hormone that plays a significant role in metabolism. The normal range for FT3 is usually between 2.3 to 4.2 pg/mL. Elevated FT3 levels may indicate hyperthyroidism, while low levels can suggest hypothyroidism.
4. Total Thyroxine (TT4)
Total Thyroxine (TT4) measures the total amount of thyroid hormone in the blood, including both bound and free thyroid hormones. The normal range for TT4 is typically between 4.5 to 12.0 µg/dL. Elevated TT4 levels may indicate hyperthyroidism, while low levels can suggest hypothyroidism.
5. Total Triiodothyronine (TT3)
Total Triiodothyronine (TT3) measures the total amount of thyroid hormone in the blood, including both bound and free thyroid hormones. The normal range for TT3 is usually between 79 to 165 ng/dL. Elevated TT3 levels may indicate hyperthyroidism, while low levels can suggest hypothyroidism.
6. Thyroid Peroxidase Antibodies (TPOAb) and Thyroglobulin Antibodies (TgAb)
Thyroid Peroxidase Antibodies (TPOAb) and Thyroglobulin Antibodies (TgAb) are blood tests that detect the presence of autoimmune thyroid diseases, such as Hashimoto’s thyroiditis and Graves’ disease. These tests are not diagnostic but can help identify individuals at risk for these conditions. Elevated levels of TPOAb and TgAb may indicate an autoimmune thyroid disorder.
In conclusion, when undergoing thyroid blood work, it is essential to check for TSH, FT4, FT3, TT4, TT3, TPOAb, and TgAb. These tests can help identify thyroid disorders and guide appropriate treatment. It is crucial to consult with a healthcare professional to interpret the results and determine the best course of action.
