7 Types of Thyroid Tests and What They Show

It is suspected that many millions of Americans have undiagnosed thyroid disorders. There are several types of thyroid tests that can be used to assess thyroid function, and each test has a specific function.

The following thyroid tests are commonly used:

1. Thyroid stimulating hormone test measures the amount of thyroid stimulating hormone in the blood. This is the hormone that is secreted by the pituitary gland to trigger the thyroid to produce its hormones. A higher than normal TSH level could indicate hypothyroidism, while a low TSH level could mean hyperthyroidism, said the American Thyroid Association.

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2. Free T4 and Free T4 Index tests measure the amount of the thyroid hormone T4 circulating in the blood. In general, a high level of T4 indicates hyperthyroidism, and a low level of T4 could mean hypothyroidism. The results of T4 tests are often combined with TSH results to confirm thyroid disorder and localize the problem to the pituitary gland or the thyroid gland.

3. T3 thyroid tests are often used in patients with suspected hyperthyroidism. Hyperthyroidism is usually indicated by high readings on the T3 test. This test is not helpful for detecting hypothyroidism, however.

4. Thyroid antibody tests measure the levels of antibodies in the blood that can cause thyroid disorders. This test can confirm the autoimmune diseases Hashimoto’s thyroiditis and Graves’ disease, both of which cause thyroid dysfunction.

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5. Iodine uptake scan is done to test how well the thyroid gland absorbs and uses iodine to make thyroid hormone, says EndocrineWeb. Hypothyroid patients generally have low iodine uptake while hyperthyroid patients usually have very high iodine uptake.

6. Thyroid scans are used to identify nodules on the thyroid gland, swelling or goiter, and to follow up on thyroid cancer treatment.

7. Thyroid needle biopsy, according to EndocrineWeb, is highly effective for determining whether or not nodules on the thyroid gland are cancerous or benign.

The appropriate thyroid tests for each patient’s concerns will be determined by a physician. WebMD advised patients undergoing thyroid tests to inform their doctors of all medications and supplements they are taking since certain medications can skew the results of thyroid tests.

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