T4 Test
Alternate Names : Thyroxine Test
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What do Abnormal Results Mean?
Greater-than-normal levels of thyroxine along with suppressed (lower than normal) levels of TSH may indicate:
Lower-than-normal levels may indicate:
- hypothyroidism (including: later Hashimoto's disease, cretinism, myxedema, goitrous diseases, following radioiodine or surgical thyroid ablation, infiltrative diseases such as scleroderma, amyloid goiter, or hemochromatosis, following neck irradiation for head and neck cancer)
- decreased conversion of T3 to T4, as in:
- malnutrition
- systemic illness
- fasting
- use of certain prescribed medication, including: dexamethasone, propranolol, lithium, iodine, methimazole, propylthiouracil, interferon alfa, interleukin-2, and amiodarone
Additional conditions under which the test may be performed:
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