T3测试

定义

Triiodothyronine (T3) is a thyroid hormone. It plays an important role in the body's control of metabolism (the many processes that control the rate of activity in cells and tissues).

A laboratory test can be done to measure the amount of T3 in your blood.

选择的名字

Triiodothyronine; T3 radioimmunoassay; 中毒性结节性甲状腺肿 - T3; Thyroiditis - T3; Thyrotoxicosis - T3; 格雷夫斯病 - T3

如何执行测试

A 血液样本 是必要的.

如何准备考试

Your health care provider will tell you if you need to stop taking any medicines before the test that may affect your test result. DO NOT stop taking any medicine without first talking to your provider.

Drugs that can increase T3 measurements include:

• 避孕药
• 安妥明
• 雌激素
• 美沙酮
• 某些草药疗法

Drugs that can decrease T3 measurements include:

• 胺碘酮
• 合成代谢类固醇
• 雄激素
• Antithyroid drugs (for example, propylthiouracil and methimazole)
• 锂
• 苯妥英
• 普萘洛尔

考试的感觉如何

When the needle is inserted to draw blood, some people feel moderate pain. 其他人只感到刺痛或刺痛. Afterward, there may be some throbbing or a slight bruise. 这很快就会消失.

为什么要进行测试

This test is done to check your thyroid function. Thyroid function depends on the action of T3 and other hormones, including thyroid-stimulating hormone (TSH) and T4.

Sometimes it can be useful to measure both T3 and T4 when evaluating thyroid function.

The total T3测试 measures the T3 that is both attached to proteins and floating free in the blood.

The free T3测试 measures only the T3 that is floating free in the blood. The tests for free T3 are generally less accurate than for total T3.

Your provider may recommend this test if you have signs of a thyroid disorder, including:

• The pituitary gland does not produce normal amounts of some or all of its hormone (垂体机能减退)
• 甲状腺过度活跃(甲状腺机能亢进)
• 甲状腺功能减退(甲状腺功能减退)
• 服用治疗甲状腺功能减退的药物

正常的结果

正常值的范围为:

• Total T3 -- 60 to 180 nanograms per deciliter (ng/dL), or 0.9 to 2.每升8纳摩尔(nmol/L)
• Free T3 -- 130 to 450 picograms per deciliter (pg/dL), or 2.0 to 7.0皮摩尔/升

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.

Normal values are age specific for people less than age 20. Check with your provider about your specific results.

异常结果意味着什么

A higher-than-normal level of T3 may be a sign of:

• 甲状腺过度活跃(for example, 格雷夫斯病)
• T3 甲状腺毒症 (罕见)
• 中毒性结节性甲状腺肿
• Taking thyroid medicines or certain supplements (common)
• 肝脏疾病

A high level of T3 may occur in pregnancy (especially with morning sickness at the end of the first trimester) or with the use of birth control pills or estrogen.

A lower-than-normal level may be due to:

• Severe short-term or some long-term illnesses
• Thyroiditis (swelling or inflammation of the thyroid gland -- 桥本病 是最常见的类型)
• 饥饿
• 甲状腺功能减退

Selenium deficiency causes a decrease in the conversion of T4 to T3, but it is not clear that this results in lower than normal T3 levels in people.

风险

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a 血液样本 from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

• 大出血
• 昏厥或感到头晕
• 多次穿刺定位静脉
• Hematoma (blood buildup under the skin)
• Infection (a slight risk any time the skin is broken)

参考文献

Guber HA, Oprea M, Rusell YX. 内分泌功能评价. 见:McPherson RA, Pincus MR，编辑. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 25.

金，南迪-蒙什D, Diblasi CC. 甲状腺疾病甲状腺疾病. 见:Gleason CA, Juul SE编. 艾弗里新生儿病. 10日艾德. Philadelphia, PA: Elsevier; 2018:chap 98.

Salvatore D, Cohen R, Kopp PA, Larsen PR. Thyroid pathophysiology and diagnostic evaluation. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. 威廉斯内分泌学教科书. 14日艾德. Philadelphia, PA: Elsevier; 2020:chap 11.

Weiss RE, Refetoff S. 甲状腺功能检查. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. 内分泌学:成人和儿童. 7日艾德. Philadelphia, PA: Elsevier Saunders; 2016:chap 78.