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Medical Video: Understanding The Dexamethasone Suppression Test
Definition
What is a dexamethasone suppression test?
The Dexamethasone suppression test will measure whether the process of adrenocorticotropic hormone (ACTH) secretion can be suppressed. This medical test examines a disease where the adrenal gland produces large amounts of cortisol (Cushing's syndrome).
When do I have to undergo a dexamethasone suppression test?
This medical test is done when the doctor suspects your body has produced cortisol beyond normal limits. This test is done to help diagnose the symptoms of Cushing's syndrome and identify the cause. A low dose test will show whether your body produces excess ACTH. While a high dose test will help determine whether the problem is rooted in the pituitary gland. Dexamethasone is an artificial (synthetic) steroid similar to cortisol. This type of steroid serves to reduce the rate of ACTH release in a normal person. Consumption of dexamethasone will lead to a reduction in the amount of ACTH and a decrease in the level of cortisol in the body.
If the pituitary gland produces excess ACTH, you will react abnormally to low-dose tests. However, you can check the normal response to the high-dose test results.
Prevention & warning
What should I know before undergoing a dexamethasone suppression test?
Like most blood tests, there is a minimal risk of mild bruising at the injection site. In rare cases, blood vessels will swell after a blood sample is taken. This condition, called pheblitis, can be treated with warm compresses several times a day. Continuous bleeding can be a problem if you suffer from a bleeding disorder or are using blood thinning drugs such as warfarin (Coumadin) or aspirin.
Some doctors estimate that a 24-hour cortisol-free urine test will be more accurate than a full-night dexamethasone suppression test. Cortisol-free 24-hour urine test is used to look for signs of Cushing's syndrome. Furthermore, see the topic of Cortisol in Urine. Adrenocorticotropic hormone (ACTH) may be done at the same time as the cortisol test.
Process
What should I do before undergoing a dexamethasone suppression test?
You will be asked not to eat and drink anything for 10-12 hours before the procedure day.
Some drugs can affect test results. Be sure to tell your doctor about the prescription and nonprescription medicines you are taking. You may be asked to stop taking certain drugs (contraceptive pills, aspirin, morphine, methadone, lithium, monoamine oxidase inhibitors [MAOIs], and diuretics) within 24 - 48 hours before blood sampling.
If you have questions related to needs during the test, risks that may be faced, test procedures, or possible results, consult your doctor for a better understanding.
What is the dexamethasone suppression test process?
The night before sampling (usually at 11 noon), you will take a pill containing 1 mg dexamethasone. In the morning, usually at 8 in the morning, the medical officer will take a sample of your blood. Avoid pills with milk or antacids to prevent ulcers.
When taking blood, medical personnel will:
- wrap an elastic belt around your upper arm to stop the blood flow. This makes the blood vessels under the bond enlarge making it easier to inject needles into the vessels
- clean the part to be injected with alcohol
- inject a needle into a vein. More than one needle may be needed.
- attach the tube to the syringe to fill it with blood
- remove the ties from your arms when taking blood is enough
- attach gauze or cotton to the injected part, after the injection is finished
- put pressure on the part and then put on a bandage
Sometimes, extensive dexamthasone suppression tests can be performed. Especially for this test, you will consume 8 pills in 2 days and then the medical officer will measure cortisol levels in your blood and urine.
What should I do after undergoing a dexamethasone suppression test?
You can immediately return home after this procedure. You may not feel anything from the syringe, unless the feeling is lightly stung when the needle is inserted into the vessel. Test results can generally be taken within a few days. Abnormal test results have the chance to get a series of follow-up tests at the advice of your doctor, to identify Cushing's syndrome. Normal test results mean you are not infected with Cushing's syndrome.
Explanation of Test Results
What do the test results mean?
Normal results
Normal results will show cortisol levels in the body less than 5 mcg / dL or less than 138 nanomole per liter (nmol / L).
Abnormal results
Abnormal results will show:
- Cortisol levels are more than normal, which indicates that you have Cushing's syndrome.
- other health problems, such as the potential for heart attack or heart failure, fever, poor diet, hyperthyroidism, depression, anorexia nervosa, uncontrolled diabetes, or alcohol dependence
- cancer that produces ACTH, such as lung cancer
Depending on the laboratory of your choice, the normal range of creatinine testing can vary. Discuss the questions you have about the results of your health test with your doctor.
Hello Health Group does not provide medical advice, diagnosis or treatment.
