This test measures the level of steroid hormones, 11-deoxycortisol, cortisol, and adrenocorticotrophic hormone (ACTH), in blood. This test also measures the level of by-products of these hormones in urine. This test is done after taking a dose of metyrapone, a drug that decreases cortisol production. It is used to help evaluate the pituitary gland's ability to produce ACTH in response to a decreased cortisol level. This test is used when an ACTH-producing tumor, Cushing's syndrome, or adrenal insufficiency are suspected.
Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. You may need this test if you have:
When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.
Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.
The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.
Depending on the method used for this test, blood or urine may need to be collected more than once, over multiple days, or at specific times. Talk to your healthcare worker about when and how often you will need to have this test.
Depending on the method used for this test, you may need to take a medication the night before the test. Ask your healthcare worker for information about how to prepare for this test, including when you will need to take medication.
Tell the person doing the test if you are pregnant.
Before having blood collected, tell the person drawing your blood if you are allergic to latex. Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. Also tell the healthcare worker if you have felt nauseated, lightheaded, or have fainted while having blood drawn in the past.
24 hour urine collection:
During a 24-hour urine collection, follow your usual diet and drink fluids as you ordinarily would, unless healthcare workers give you other instructions. Avoid drinking alcohol before and during the urine collection.
A sample of venous blood and a 24 hour urine collection may be collected for this test.
Methods used collect a sample for this test vary. Depending on the method used, you may need a sample collected more than once, over multiple days, or at specific times. Ask the healthcare worker to explain the details of this test to you.
When a blood sample from a vein is needed, a vein in your arm is usually selected. A tourniquet (large rubber strap) may be secured above the vein. The skin over the vein will be cleaned, and a needle will be inserted. You will be asked to hold very still while your blood is collected. Blood will be collected into one or more tubes, and the tourniquet will be removed. When enough blood has been collected, the healthcare worker will take the needle out.
24 hour urine collection:
For a 24-hour urine collection, all of the urine that you pass over a 24-hour time period must be collected. If you are in the hospital, a healthcare worker will collect your urine. You will receive a special container to collect the sample in if you are doing the collection at home. The following are directions for collecting a 24-hour urine sample while at home:In the morning scheduled to begin the urine collection, urinate in the toilet and flush away the first urine you pass. Write down the date and time. That is the start date and time for the collection.Collect all urine you pass, day and night, for 24 hours. Use the container given to you to collect the urine. Avoid using other containers. The urine sample must include the last urine that you pass 24 hours after starting the collection. Do not allow toilet paper, stool, or anything else to be added to the urine sample.Write down the date and time that the last sample is collected. The urine sample may need to be kept cool during the 24-hour collection period. If so, keep the closed container in a pan on ice. Do not put ice in the container with the urine.
The amount of discomfort you feel will depend on many factors, including your sensitivity to pain. Communicate how you are feeling with the person doing the test. Inform the person doing the test if you feel that you cannot continue with the test.
During a blood draw, you may feel mild discomfort at the location where the blood sample is being collected.
24 hour urine collection:
This test usually causes no discomfort.
After a blood sample is collected from your vein, a bandage, cotton ball, or gauze may be placed on the area where the needle was inserted. You may be asked to apply pressure to the area. Avoid strenuous exercise immediately after your blood draw. Contact your healthcare worker if you feel pain or see redness, swelling, or discharge from the puncture site.
24 hour urine collection:
When 24-hour urine collection is complete, close the container and seal the lid tightly. Return the sample in the urine container to the facility or healthcare worker as instructed. If you had the sample in an ice bath, return the sample within two hours after removing the container from the ice bath.
Blood: During a blood draw, a hematoma (blood-filled bump under the skin) or slight bleeding from the puncture site may occur. After a blood draw, a bruise or infection may occur at the puncture site. The person doing this test may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of this test.
Urine: A urine test is generally considered safe. Talk to your healthcare worker if you have questions or concerns about this test.
Ask your healthcare worker for the normal results of this test.
Normal levels are indication specific, patient specific and technique specific .
Drug Therapy Use:
Some medications may affect the results of the test. These medications include:
Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.
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 Suliman AM, Smith TP, Labib M, et al: The low-dose ACTH test does not provide a useful assessment of the hypothalamic-pituitary-adrenal axis in secondary adrenal insufficiency. Clin Endocrinol (Oxf) 2002; 56(4):533-539.
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 Girard J, Eberle AN, & Baumann JB: Plasma ACTH in diagnosis and control of adrenal disorders. Acta Endocrinol Suppl 1986; 279:254-8.
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 Tietz NW (Ed): Clinical Guide to Laboratory Tests, 3rd ed. W. B. Saunders, Philadelphia, PA, 1995.