Low TSH and high FT4 (and FT3) This is the picture of primary hyperthyroidism and, in this context, TSH is usually undetectable (typically <0.03 mU/l for modern ultrasensitive TSH assays). In the UK, Graves’ disease (GD) and toxic multinodular goitre (MNG) are the two most common causes . High TSH and low FT4 (and FT3)

Sep 5, 2023 · Patients who are hyperthyroid will have an elevated T3 level. In some individuals with a low TSH, only the T3 is elevated and the FT4 or FTI is normal. T3 testing rarely is helpful in the hypothyroid patient, since it is the last test to become abnormal.

Oct 11, 2024 · High levels of fT4 typically indicate hyperthyroidism, whereas low fT4 levels suggest hypothyroidism (13). T3 is the active thyroid hormone that directly influences metabolic processes within cells.

Feb 27, 2025 · This thyroid test analyzer will help you understand your TSH, T3, T4, and other thyroid function test results. Select a test and enter your lab value to learn more.

Feb 14, 2022 · Triiodothyronine, also known as T3, is one of the two main thyroid hormones. Thyroxine, or T4, is the other hormone. Healthcare providers test T3 levels using blood tests. Triiodothyronine comes in two forms: Free T3: This form enters your body’s tissues where it's …

Dec 14, 2024 · For instance, a high TSH and low T4 may suggest Hashimoto’s disease, while a low TSH and high T4 may suggest Graves' disease. Different combinations of values can mean different things, and there is often more than one meaning. Thyroid tests are done to determine how well the thyroid gland is working.

Thyroxine, also known as T4, is the major type of hormone your thyroid releases. Too much or too little T4 can indicate thyroid disease. Healthcare providers test T4 levels using blood tests. Thyroxine (T4) comes in two forms: Bound T4: This form attaches to proteins, which prevents it from entering your body’s tissues.

Low Free T3 and T4 levels: May indicate hypothyroidism, where the thyroid gland produces insufficient hormones. Symptoms often include fatigue, weight gain, depression, and sensitivity to cold. High Free T3 and T4 levels: May suggest hyperthyroidism, where the thyroid is overactive. Symptoms can include weight loss, rapid heartbeat, anxiety ...

Dec 2, 2024 · Elevated free T4 levels can indicate hyperthyroidism while low free T4 levels can indicate hypothyroidism. T4 is not the active form of thyroid hormone. Your body will convert T4 into T3 which is the active form.

May 16, 2024 · If your Free T3 level is high in your thyroid test results, it indicates that your thyroid is overactive or hyperthyroidism. If your Free T3 is low in your thyroid test results, you may not be converting T4 to Free T3 very well.