Dexamethasone suppression test

Definition

地塞米松抑制试验测量肾上腺皮质醇分泌是否能被抑制. 它还可以帮助评估皮质醇在你体内过量的原因，比如是否由于垂体分泌过量的促肾上腺皮质激素(ACTH).

Alternative Names

DST; ACTH suppression test; Cortisol suppression test

How the Test is Performed

During this test, you will receive dexamethasone. 这是一种强效的人造(合成)糖皮质激素药物. 之后，抽血以便测量血液中的皮质醇水平.

有两种不同类型的地塞米松抑制试验:低剂量和高剂量. 每种类型都可以在一夜之间完成(常见)或标准(3天)方法(罕见)。. 有不同的过程可以用于这两种测试. Examples of these are described below.

Common:

• 夜间低剂量——你将在晚上11点服用1毫克地塞米松.m.十大赌博平台排行榜会在第二天早上8点给你抽血.m. for a cortisol measurement.
• 夜间高剂量——十大赌博平台排行榜会在测试的早晨测量你的皮质醇. Then you will receive 8 mg of dexamethasone at 11 p.m. Your blood is drawn the next morning at 8 a.m. for a cortisol measurement.

Rare:

• 标准低剂量—收集尿液超过3天(储存在24小时收集容器中)以测量皮质醇. On day 2, you will get a low dose (0.每6小时口服地塞米松5毫克，持续48小时.
• 标准高剂量-收集尿液超过3天(储存在24小时收集容器中)用于测量皮质醇. 在第2天，您将每6小时口服高剂量(2毫克)地塞米松，持续48小时.

Read and follow the instructions carefully. 不正常的测试结果最常见的原因是没有遵循说明.

How to Prepare for the Test

你的十大赌博平台排行榜可能会告诉你停止服用某些可能影响测试的药物，包括:

• Antibiotics
• Anti-seizure medicines
• 含有皮质类固醇的药物，如氢化可的松、强的松
• Estrogen
• Oral birth control (contraceptives)
• Water pills (diuretics)

How the Test will Feel

当针头插入抽血时，有些人会感到中度疼痛. Others feel only a prick or stinging. 之后，可能会有一些悸动或轻微的瘀伤. This soon goes away.

Why the Test is Performed

当你的十大赌博平台排行榜怀疑你的身体产生过多的皮质醇时，就可以做这个测试. It is done to help diagnose Cushing syndrome and identify the cause.

低剂量测试可以帮助判断你的身体是否产生了过多的ACTH. 高剂量试验可以帮助确定问题是否出在脑垂体(Cushing disease) or from a different site in the body (ectopic).

地塞米松是一种人造类固醇，与皮质醇结合在同一受体上. Dexamethasone reduces ACTH release in normal people. 因此，服用地塞米松应能降低ACTH水平并导致皮质醇水平降低.

If your pituitary gland produces too much ACTH, you will have an abnormal response to the low-dose test. But you can have a normal response to the high-dose test.

Normal Results

皮质醇水平在接受地塞米松治疗后应该会下降.

Low dose:

• Overnight -- 8 a.m. plasma cortisol lower than 1.8微克每分升(mcg/dL)或50纳摩尔每升(nmol/L)
• 标准-第3天尿中游离皮质醇低于每天10微克(微克/天)或280纳摩尔/升

High dose:

• 一夜之间，血浆皮质醇降低了50%以上
• 标准，尿中游离皮质醇减少90%以上

不同实验室的正常值范围可能略有不同. 一些实验室使用不同的测量方法或可能测试不同的标本. 与你的医疗保健提供者谈谈你的具体测试结果的意义.

What Abnormal Results Mean

对低剂量测试的异常反应可能意味着你的皮质醇释放异常(库欣综合征)。. This could be due to:

• Adrenal tumor that produces cortisol
• Pituitary tumor that produces ACTH
• Tumor in the body that produces ACTH (ectopic Cushing syndrome)

高剂量试验可以帮助区分垂体病因(库欣病)和其他病因. ACTH血液检查也可以帮助确定高皮质醇的原因.

异常结果因引起问题的十大赌博靠谱网络平台而异.

Cushing syndrome caused by an adrenal tumor:

• Low-dose test -- no decrease in blood cortisol
• ACTH level -- low
• In most cases, the high-dose test is not needed

Ectopic Cushing syndrome:

• Low-dose test -- no decrease in blood cortisol
• ACTH level -- high
• High-dose test -- no decrease in blood cortisol

垂体瘤引起的库欣综合征(库欣病)

• Low-dose test -- no decrease in blood cortisol
• High-dose test -- expected decrease in blood cortisol

False test results can occur due to many reasons, including different medicines, obesity, depression, and stress. False results are more common in women than men.

Most often, 在早晨测量血液中的地塞米松水平和皮质醇水平. For the test result to be considered accurate, 地塞米松水平高于200纳克/分升(ng/dL)或4.5 nanomoles per liter (nmol/L). 地塞米松水平较低可能导致假阳性测试结果.

Risks

抽血没有什么风险. 静脉和动脉的大小因人而异, and from one side of the body to the other. 从某些人身上采血可能比从其他人身上采血更困难.

其他与抽血相关的风险很小，但可能包括:

• Excessive bleeding
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

References

Bertholf RL, Cooper M, Winter WE. Adrenal cortex. 1 .陈永祥，陈永祥，陈永祥，陈永祥，陈永祥，陈永祥，等. Tietz Textbook of Laboratory Medicine. 7th ed. Philadelphia, PA: Elsevier; 2023:chap 56.

Guber HA, Oprea M, Russell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. 亨利氏病的临床诊断及实验室方法处理. 24th ed. St Louis, MO: Elsevier; 2022:chap 25.

Newell-Price JDC, Auchus RJ. The adrenal cortex. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ编. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 15.