A thyroid-stimulating hormone (TSH) test measures the amount of TSH in the blood. TSH is produced by the pituitary gland, which is located at the base of your brain. It’s responsible for regulating the amount of hormones released by the thyroid.

The thyroid is small, butterfly-shaped gland located in the front of the neck. It’s an important gland that creates three primary hormones:

  • triiodothyronine (T3)
  • 甲状腺素（T4）
  • 降钙素

The thyroid controls numerous different bodily functions, including metabolism and growth, through the release of these three hormones.

如果您的垂体产生更多TSH，甲状腺将产生更多的激素。通过这种方式，这两个腺体共同起作用，以确保产生适量的甲状腺激素。

However, when this system is disrupted, your thyroid can produce either too many or too few hormones.

A TSH test is often performed to determine the underlying cause of abnormal thyroid hormone levels. It’s also used to screen for an underactive or overactive thyroid gland. By measuring the level of TSH in the blood, your doctor can determine how well the thyroid is working.

如果您患有甲状腺疾病的症状，您的医生可能会订购TSH测试。甲状腺疾病可以归类为甲状腺功能减退症或甲状腺功能亢进。

甲状腺功能减退症

甲状腺功能减退症是甲状腺产生太少激素的条件，导致新陈代谢减慢。甲状腺功能减退的症状包括fatigue，弱点，difficulty concentrating.

The following are some of the most common causes of hypothyroidism:

  • 桥本的甲状腺炎。这是一个n自身免疫性状况这会导致身体攻击自己的甲状腺细胞。结果，甲状腺无法产生足够数量的激素。这种情况并不总是会引起症状，因此它可以在几年内进展，然后才会造成明显的损害。
  • Thyroiditis.这是一个n inflammation of the thyroid gland. It’s often caused by a viral infection or an autoimmune disorder, such as Hashimoto’s thyroiditis. This condition interferes with thyroid hormone production and eventually leads to hypothyroidism.
  • 产后甲状腺炎。这是甲状腺炎的暂时形式，在分娩后可能会发展。
  • Iodine deficiency.The thyroid uses iodine to produce hormones. An iodine deficiency can lead to hypothyroidism. It’s extremely rare in the United States due to the widespread use of iodized salt. However, it’s more common in other regions of the world.

甲状腺功能亢进

甲状腺功能亢进是甲状腺产生过多激素的条件，导致新陈代谢加快。甲状腺功能亢进症的症状包括食欲增加，焦虑和睡眠困难。

以下是甲状腺功能亢进的一些最常见原因：

  • 坟墓的疾病。这是一个常见障碍其中甲状腺变大并产生过量的激素。该疾病具有与甲状腺功能亢进症相同的许多症状，并且经常有助于甲状腺功能亢进的发展。
  • Thyroiditis.It eventually leads to hypothyroidism, but in the short term, it can also trigger hyperthyroidism. This may occur when the inflammation causes the thyroid to produce too many hormones and release them all at once.
  • Excess iodine.体内过多的碘会导致甲状腺变得过度活跃。这通常是由于连续使用含有碘的药物而发生的。这些药物包括一些用于治疗心律不齐的咳嗽糖浆和氨二酮。
  • Thyroid nodules.这些都是良性肿块that sometimes form on the thyroid. When these lumps begin to increase in size, they may become overactive and the thyroid may start producing too many hormones.

TSH测试不需要任何特殊准备。但是，重要的是要告诉医生您是否正在服用可能干扰TSH测量准确性的药物。一些可能干扰TSH测试的药物是：

  • 胺碘酮
  • dopamine
  • 锂
  • 强的松
  • potassium iodide
  • 生物素

You may need to avoid using these drugs before the test. However, don’t stop taking your medications unless your doctor tells you to do so.

A TSH test involves taking a sample of blood. The blood is typically drawn from a vein that’s inside the inner elbow.

A healthcare provider will perform the following procedure:

  1. 首先，他们将使用杀菌剂或其他灭菌溶液清洁该区域。
  2. 然后，他们会在您的手臂上绑上一个弹性带，使静脉充满血液。
  3. Once they find a vein, they’ll insert a needle into the vein to draw blood. The blood will be collected in a small tube or vial attached to the needle.
  4. After they draw enough blood, they’ll remove the needle and cover the puncture site with a bandage to stop any bleeding.

The entire procedure should only take a few minutes to complete. The blood sample will be sent to a lab for analysis.

Once your doctor receives the test results, they’ll schedule an appointment with you to discuss the results and explain what they may mean.

TSH水平的正常范围为每升0.4至4.0毫米内部单位。如果您已经因甲状腺障碍而受到治疗，则正常范围为每升0.5至3.0毫米分离单位。

高于正常范围的值通常表明甲状腺不足。这表明甲状腺功能减退症。当甲状腺没有产生足够的激素时，垂体腺会释放出更多的TSH来刺激它。

低于正常范围的值表示甲状腺过度活跃。这表明甲状腺功能亢进。当甲状腺产生过多的激素时，垂体腺会释放出较少的TSH。

Depending on the results, your doctor may want to perform additional tests to confirm the diagnosis.