Overnight suppression test with 1 mg dexamethasone. When does it become necessary to perform a small dexamethasone test? What may interfere with the dexamethasone suppression test?

A dexamethasone test is needed to detect elevated levels of cortisol in a person’s blood. Not many people know what dexamethasone is - it is a hormone produced by the adrenal cortex, it should be noted that it is the strongest and most powerful among them.

This test also makes it possible to identify various hormonal disorders and establish the main reason why the fair sex may experience irregular menstrual cycles. In addition, the dexamethasone test can reveal pathological disorders in the female reproductive system and clearly identify the reasons for the appearance of traits that are inherent only in representatives of the stronger half of humanity.

A dexamethasone test is prescribed to patients with increased levels of production male hormones. Only similar procedure is able to identify the source of the violation and establish its nature. It has been scientifically proven that hormonal tests are the most effective and accurate diagnostic procedures. That is why at the slightest hormonal imbalance any representative of the fair sex should immediately contact a medical facility and make an appointment with a specialist. Only a doctor, after the results of an appropriate examination, will be able to prescribe the necessary sample to the patient.

As previously mentioned, a test with dexamethasone is prescribed only to those patients in whom it is necessary to identify the main cause of the manifestation male characteristics, such as testosterone. Such signs usually occur due to excessive production of male hormones in female body. It should be noted that depending on the dose, the sample may be:

• A small dexamethasone test can be performed in a specialized medical institution two methods - classic and shortened. The first method is that the patient takes blood on the first day at eight in the morning, which is necessary to determine the level of cortisol. Then, over the next two days, the patient should take one dexamethasone tablet every six hours. On the third day, at exactly eight in the morning, a repeat analysis is carried out. This is a fairly sensitive method, because its result is 97-100%. The second method - on the first day at eight in the morning, blood is also taken from the patient to determine the level free cortisol. At eleven o'clock in the evening of the same day, the patient must take two dexamethasone tablets at once, and the next day be tested again. Sensitivity this method will be slightly lower and will be approximately 95%, however, you will be able to get the result faster. As for the results, their interpretation will be the same for both options. So, for example, if the results of the study reveal that cortisol has dropped by half, then the test is positive;
• A large dexamethasone test is prescribed by a specialist, provided that the small one shows negative result. IN in this case During the study, a large dose of dexamethasone is used. To carry out such a test, two methods are also used - classic and shortened. The first method is practically no different from that used for a small dexamethasone test, the only difference is in the number of tablets - the patient takes four every six hours, after which he is tested again. A shortened version of the large dexamethasone test involves taking sixteen tablets at a time. Samples are interpreted in the same way, regardless of the method. If the results of the study reveal a decrease in cortisol by fifty percent from the original level, the test will be considered positive. If no changes are noted, the sample will be considered negative.

The differences between these samples lie not only in the dosage, but also in the process itself. A small test, or also called a short test, allows specialists to distinguish exogenous hypercortisolism from endogenous one. As a rule, exogenous refers to too much intake of various drugs into the body and an increase in normal level cortisol.

This hormone can increase in human body for obesity, excessive consumption alcoholic beverages, diabetes and pregnancy. Usually, when the underlying cause is eliminated, the hormone comes into normal condition and no longer bothers the person.

Preparatory stages

No special preparation is required from the patient to determine the level of the hormone in the blood; experts recommend that their patients refrain from taking any painkillers the day before the test. The dexamethasone test involves taking the drug strictly according to the regimen, which, as a rule, can only be prescribed by the treating doctor.

In addition, the specialist must strictly monitor compliance with the prescribed dosage and time intervals. Therefore, experimenting with the dosage and breaking the rules will not work in any case. Unauthorized prescription of the drug will not lead to anything good, the patient must understand this.

It is not necessary to follow any diet before donating blood and detecting hormone levels. The only limitation is that it is not recommended to eat or drink water approximately ten hours before the test. Also, be sure to tell your doctor about any medicines, which you accept on at the moment– this is very important, since many of them can have a direct impact on the test results.

Otherwise, you will have to take the test again. It is likely that after announcing the medications you are taking, the doctor will decide to prohibit some of them in order to achieve the most accurate result. If the test is performed at night, the patient will be warned that they will have to spend the night at the medical center.

Hormonal tests allow you to obtain the most accurate results, which may indicate one or another disorder associated with the normal production of the hormone. As a result of such a test, a specialist can detect the following diseases or deviations:

• Adrenal tumor;
• Ovarian tumor;
• Adrenal hyperplasia;
• Cyst;
• Pituitary tumor;
• Chorionepithelioma of the ovary.

In fact this is far from full list diseases that can be identified as a result of the study. It is also worth noting that the dexamethasone test is simply irreplaceable if a specialist needs to confirm the presence of Cushing’s syndrome and hypercortisolemia. Similar studies often practiced by specialists in the field of gynecology, thanks to them it becomes possible to identify even the most subtle deviations in the secretion of a particular hormone.

According to the results obtained, the specialist can determine the reason for the absence menstrual cycle, excessive production of male hormones, infertility and various tumors. All procedures are absolutely painless and do not cause any discomfort, so do not be afraid.

What can interfere with the test?

There are certain reasons that may affect the test results, these include: pregnancy, obesity, diabetes, great loss weight, sudden cessation of abuse alcoholic drinks, fast metabolism, and serious injuries.

Typically, when found similar reasons, the specialist decides to cancel the study, the patient must understand that in this case it will simply be pointless, and it will not be possible to establish the correct hormone level. It is possible that the patient will be offered alternative option, but keep in mind that it will not give the most accurate and effective results.

Many patients who are prescribed a test to detect levels of a hormone called cortisol by a specialist wonder what complications or risks there may be after the procedure. Any serious complications was not noticed. Possible risk may only be associated with the procedure of drawing blood from a vein, which will result in a slight bruise at the puncture site.

In some cases inflammation of the vein was observed, but warm compresses, which are applied to the hand several times a day, quickly relieve patients from such incidents. Also, if at the time of the test you were taking or are taking any medications that thin the blood, then you may experience slight bleeding at the puncture site.

Remember that if you detect any hormonal abnormalities, you do not need to put off your visit to the doctor, do not be lazy, but immediately seek qualified help. You cannot solve such problems on your own, otherwise everything could be much more serious later. Detect and eliminate any disease on initial stage much easier than later. In addition, the procedure for identifying the level of a hormone called cortisol is quite simple, painless and will not take much of your time.

The dexamethasone test is used to diagnose depression. It is based on the fact that during depression the levels of corticosteroids and cortisol increase. After administration of 1 mg. dexamethasone, the amount of ACTH (adrenocorticotropic hormone) decreases, and cortisol levels remain high.

The table provides information about physiological basis dexamethasone test.

In the 1980s, the dexamethasone test was used more often. Its sensitivity was 44% and specificity -93% for depression (Arana et Baldessarini). If patients had other mental disorders, then the specificity indicators decreased. At panic attacks and anxiety up to 88.2%, with schizophrenia – 86.9%, alcoholism – 80%.

A number of researchers have recorded positive results dexamethasone test for obsessive-compulsive disorder.

Gender and age did not affect the dexamethasone test, but in older people its values ​​could be higher.

Antipsychotics, antidepressants, lithium preparations do not affect the test results, but barbiturates, benzodiazepines, anticonvulsants may lead to a false positive result.

False-positive results are also observed with alcohol intoxication and caffeine intake.

Similar data occur with brain tumors, diabetes mellitus, Addison’s disease, Itsenko-Cushing’s disease, cardiovascular failure, infectious diseases, injuries, pregnancy. This is an indication that the dexamethasone test is relatively specific.

But still, the indicators of the dexamethasone test are normalized when one comes out of depression, and his increased performance may reflect a negative prognosis and increased risk suicide.

Big diagnostic value the dexamethasone test has psychotic depression and bipolar affective disorder.

The sensitivity of the test is associated with a genetic predisposition to depression. The biochemical basis of the test is a change in the sensitivity of receptors to glucocorticoids, which leads to low level ACTH in response to administration of corticotropin-releasing factor. There is also no suppressive effect on cortisol levels when administered dexamethasone (a synthetic glucocorticoid). Thus, despite some disadvantages, the dexamethasone test can be used in the treatment of depression.

Dexamethasone test used to detect hypercortisolism ( higher level cortisol in the blood). In this article you will learn how and when a dexamethasone test is performed.

Large doses include non-physiological doses of the drug, i.e. those that exceed the replacement dose by several times. This response to dexamethasone is dose-dependent, that is, it depends on the dose administered. This is what they are based on different options dexamethasone test.

How is the dexamethasone test performed?

Dexamethasone test depending on the dose it may be:

1. Small dexamethasone test.
2. Large dexamethasone test.

Small dexamethasone test

A small dexamethasone test allows one to distinguish exogenous hypercortisolism from endogenous one.

Exogenous hypercortisolism includes:

• Excessive intake of glucocorticoid drugs in various diseases
• Increased cortisol levels with

1. obesity
2. alcoholism
3. diabetes mellitus
4. diencephalic syndrome
5. chronic hepatitis and liver cirrhosis
6. pregnancy

This increase in cortisol in the blood (in addition to excess intake of drugs) is also called functional hypercortisolism. Cortisol levels decrease when the cause is eliminated.

The small one is carried out as follows. There are several options for conducting the test: classic and shortened.

Classic version T.

On the first day at 8:00 a.m. blood is drawn to determine baseline cortisol. Then, 0.5 mg (1 tablet) of dexamethasone is taken every 6 hours for 48 hours. On the third day in the morning at 8:00 am, the level of free cortisol is determined again. The sensitivity of the method is 97-100%.

Short version.

On the first day at 8:00 - blood sampling for the initial level of free cortisol. At 23:00 on the same day, the patient takes 1 mg (2 tablets) of dexamethasone. On the second day in the morning at 8:00 - a repeated blood draw to determine free cortisol. The sensitivity of the method is slightly lower - 95%.

Interpretation of results.

The interpretation of the results is the same for both options. Normally and with functional hypercortisolism, cortisol levels decrease by more than 2 times. In this case, the sample is considered positive.

With endogenous hypercortisolism, the test is negative, because there are foci of autonomous hormone secretion that are not affected by the administered dexamethasone at this dose.

Large dexamethasone test

When installed endogenous cause increased levels of cortisol in the blood, i.e. small sample turned out to be negative, a large dexamethasone test is performed. This test will allow you to distinguish between the disease and Cushing's syndrome. Read more about this syndrome. A large dose of dexamethasone is used here. This sample also has 2 options: classic and shortened.

Classic version.

On the first day at 8:00 am the initial level of free cortisol in the blood is determined. Then, for 48 hours, 2 mg (4 tablets) of dexamethasone is taken every 6 hours. On the third day at 8:00 am, blood samples are taken again for free cortisol.

Shortened version T.

On the first day at 8:00, blood is also taken and the initial level of free cortisol is determined. At 23:00 on the same day, the patient takes 8 mg (16 tablets) of dexamethasone. On the second day at 8:00 - repeated blood sampling for free cortisol.

Interpretation of results.

The interpretation of the sample is the same in both cases.

When taking a large dose of dexamethasone for Cushing's disease, the level of free cortisol decreases by 50% or more from the original level. The test is considered positive. Read about Itsenko Cushing's disease.

With adrenal forms of Itsenko Cushing, as well as with a decrease, this does not occur and the test remains negative.

Thus, it is an excellent tool in the diagnosis of diseases that occur with symptoms of hypercortisolism.

With warmth and care, endocrinologist Dilyara Lebedeva

... timely diagnosis and adequate treatment can improve the quality of life of patients and reduce the risk of death.

Endogenous hypercortisolism or Cushing's syndrome is a complex clinical symptoms, which are caused by long-term effects of corticosteroids on the body due to their excess endogenous production. Endogenous hypercortisolism can be ACTH-dependent (most often) and ACTH-independent (ACTH adrenocorticotropic hormone). Most common cause ACTH-dependent hypercortisolism is pituitary corticotropinoma (Cushing's disease or hypercortisolism central genesis), less often - ectopic production of ACTH by a tumor or, extremely rarely, ectopic production of corticotropin-releasing hormone. In most cases, the cause of ACTH-independent hypercortisolism is a tumor of the adrenal cortex (corticosteroma or, less commonly, adrenocortical carcinoma). Let's look at the basic principles and tests laboratory diagnostics endogenous hypercortisolism.

Remember! In practice, the most common cause of development clinical signs hypercortisolism is the exogenous intake of glucocorticoids, and therefore before the diagnostic studies It is extremely important to exclude the causes of the development of endogenous hypercortisolism:
Firstly, possible options ingestion of corticosteroid drugs;
secondly, pseudocushingoid states (otherwise - functional hypercortisolism), which are accompanied by hypercortisolemia without the development of clear clinical signs of hypercortisolism (depression and other mental disorders, alcoholism, obesity, hypothalamic syndrome, uncompensated diabetes mellitus, liver disease, pregnancy).

According to the recommendations of the European Society of Endocrinology (2008) examination for the presence of endogenous hypercortisolism is prescribed in following cases :
availability pathological conditions that are not age appropriate: osteoporosis, arterial hypertension in young people;
presence of several progressive pathological symptoms that are pathognomonic for hypercortisolism (eg, dysplastic obesity, trophic changes skin, proximal myopathy - muscle weakness and muscle atrophy, menstrual irregularities and decreased libido as a consequence of secondary hypogonadism, hirsutism, etc.)
the appearance of purple stretch marks more than 1 cm wide;
combination of growth disturbance and weight gain in children;
the presence of an incidentaloma (an adrenal tumor that was accidentally discovered by research methods performed for other diagnostic purposes).

To determine increased production of cortisol in the body (a manifestation of hypercortisolism), the following laboratory [diagnostic] tests are used:

(1 ) Overnight suppression test with 1 mg dexamethasone(or PTD1). The test is based on the suppression of ACTH secretion and, as a consequence, a decrease in cortisol production in response to dexamethasone. Preliminary preparation not required. Maybe outpatient implementation test with confidence that the patient will take the pills on time. Methodology: the patient takes 1 mg of dexamethasone at 23.00, at 8 - 9 o'clock next morning Blood is taken to test cortisol levels. Normally, cortisol levels are suppressed below the lower limit of normal for a given laboratory, usually less than 5 mcg/dL (<3 мкг/дл по рекомендациям других авторов) или 140 (100) нмоль/л. Однако ряд исследователей предлагают использовать более жесткие критерии: снижение кортизола должно быть менее 1,8 мкг/дл (50 нмоль/л).

(2 ) 48-hour suppression test with 2 mg per day dexamethasone(or PTD2). Some authors prefer to use this test as a screening test, especially when a pseudocushingoid condition is suspected, as well as to exclude subclinical Cushing's syndrome. Procedure: dexamethasone is prescribed 0.5 mg every 6 hours for 48 hours, cortisol is determined at 9 a.m. on the 3rd day (6 hours after taking the last dexamethasone tablet). Normal cortisol levels are less than 1.8 mcg/dL (50 nmol/L).

(3 ) Study of the level of free cortisol in saliva in the evening(double definition). Normal salivary cortisol levels at 23–24 hours do not exceed 145 ng/dL (4 nmol/L) using enzyme-linked immunosorbent assay (ELISA) or mass spectrometry.

(4 ) Determination of free cortisol content in daily urine(double definition). Patients should be explained the rules for collecting daily urine: the first portion of urine after sleep is not collected, but all subsequent ones are collected, including the morning portion of the second day. The container for collecting urine should be kept in the refrigerator, but not frozen. The test has high sensitivity (95%), but low specificity (it is believed that if > 250 mcg of cortisol is excreted per day, then the presence of endogenous hypercortisolism is beyond doubt).

(5 ) Testing blood cortisol levels at 11 p.m.(used as additional test if the patient is taking anticonvulsants, as well as in case of questionable results with PTD1, and when studying the 24-hour urine cortisol content). Measurement of serum cortisol at night (23.00) can be carried out during sleep (blood should be taken no later than 5 - 10 minutes after waking up, pre-catheterization facilitates this procedure) or in a state of wakefulness. A serum cortisol level of more than 207 nmol/L (7.5 μg/dL) during wakefulness or more than 50 nmol/L (1.8 μg/dL) in a sample taken during sleep is characteristic of endogenous hypercortisolism (Cushing's syndrome ).

(6 ) Combined test: PTD2 + stimulation of corticotropin-releasing hormone(can be used if the results of determining free cortisol in daily urine are questionable, as well as the results obtained during PTD1 and PTD2. Procedure: dexamethasone is taken 0.5 mg every 6 hours for 48 hours (start of administration at 12.00 noon), corticotropin-releasing hormone at a dose of 1 mcg/kg (maximum 100 mcg) is administered intravenously at 8.00 (2 hours after taking the last dose of dexamethasone). The level of cortisol in the blood is determined after 15 minutes. Its increase is more than 1.4 mg/dl ( 38 nmol/l) confirms the diagnosis of endogenous hypercortisolism (it should be noted that corticotropin-releasing hormone preparations are currently not registered in the Russian Federation).

Large and small dexamethasone tests are an important diagnostic tool used by endocrinologists. These functional tests allow us to determine the presence of excess cortisol production, as well as the suspected cause of this phenomenon. They are necessary for the reason that analysis to determine the basal level of cortisol is a low-informative study. To conduct tests and obtain reliable results, a number of specific requirements must be met.

Small dexamethasone test

This test is called small because of the low dose of the drug used during it. A modification of this method is currently being used, which is called the overnight suppression test with Dexamethasone. This test indicates the presence of increased cortisol production and is used when identifying symptoms in a patient that are suspicious for hypercortisolism:

• specific (Cushingoid) type of obesity - thin arms and legs, redistribution of fat with deposition in the upper half of the body;
• purple stretch marks;
• moon-shaped face;
• arterial hypertension;
• menstrual irregularities and infertility in women.

Hypercortisolism occurs as a result of the autonomous production of cortisol by the adrenal cortex (corticosteroma, cortical hyperplasia) or when the synthesis of the substance is stimulated high level adrenocorticotropic hormone (ACTH) with pituitary adenoma (Cushing's disease) or ectopic ACTH syndrome (abnormal synthesis of ACTH outside the pituitary gland, occurring most often with small cell cancer lung).

Disorders in the field of gynecology occur only with Cushing's disease. With this pathology, in addition to an increase in cortisol levels, hyperandrogenism develops - an increase in the amount of male hormones in a woman’s blood.

Methodology

The test is carried out in an outpatient or inpatient conditions. No specific preparation is required for it. For women, this test can be performed on any day of the menstrual cycle. Before the test to avoid unreliable results It is advisable to discontinue the following medications:

• barbiturates for 1 day;
• anticonvulsants for 1 day;
• Rifampicin for 1 day;
• combined oral contraceptives 6 weeks before the test.

The patient must take two Dexamethasone tablets containing 1 mg at 11:00 p.m. active substance. At 8:00 the next day, blood is drawn to determine cortisol levels.

Interpretation of results

Normally, this dose of Dexamethasone suppresses the secretion of adrenocorticotropic hormone from the pituitary gland. As a result, its stimulating effect on cortisol synthesis is reduced. For this reason, in healthy people, after an overnight suppression test, cortisol levels at 8 a.m. next day does not exceed 50 nmol/l. Such a test is called positive.

If the readings are above 50 nmol/l, the test is negative, which indicates the presence of hypercortisolism, but does not allow one to determine its nature. To determine the probable cause, a large dexamethasone test is performed.

The test results should be interpreted by an endocrinologist.

Large dexamethasone test

The indication for this study is a negative overnight suppression test. Low dose Dexamethasone (1 mg) in healthy person leads to suppression of ACTH synthesis. If you have a pituitary adenoma that produces an excess amount of the substance, this does not happen.