Cortisol and Challenge Tests

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Cortisol and Challenge Tests

Synonym/acronym: Hydrocortisone, compound F.

Common use

To assist in diagnosing adrenocortical insufficiency such as found in Cushing’s syndrome and Addison’s disease.


Serum (1 mL) collected in a red- or red/gray-top tube. Plasma (1 mL) collected in a green-top (heparin) tube is also acceptable. Care must be taken to use the same type of collection container if serial measurements are to be taken.
ProcedureIndicationsMedication AdministeredRecommended Collection Times
ACTH stimulation, rapid testSuspect adrenal insufficiency (Addison’s disease) or congenital adrenal hyperplasia1 mcg (low-dose physiologic protocol) cosyntropin IM or IV; 250 mcg (standard pharmacologic protocol) cosyntropin IM or IV3 cortisol levels: baseline immediately before bolus, 30 min after bolus, and 60 min after bolus. Note: Baseline and 30 min levels are adequate for accurate diagnosis using either dosage; low dose protocol sensitivity is most accurate for 30 min level only
CRH stimulationDifferential diagnosis between ACTH-dependent conditions such as Cushing’s disease (pituitary source) or Cushing’s syndrome (ectopic source) and ACTH-independent conditions such as Cushing’s syndrome (adrenal source)IV dose of 1 mg/kg ovine or human CRH8 cortisol and 8 ACTH levels: baseline collected 15 min before injection, 0 min before injection, and then 5, 15, 30, 60, 120, and 180 min after injection
Dexamethasone suppression (overnight)Differential diagnosis between ACTH-dependent conditions such as Cushing’s disease (pituitary source) or Cushing’s syndrome (ectopic source) and ACTH-independent conditions such as Cushing’s syndrome (adrenal source)Oral dose of 1 mg dexamethasone (Decadron) at 11 p.m.Collect cortisol at 8 a.m. on the morning after the dexamethasone dose
Metyrapone stimulation (overnight)Suspect hypothalamic/pituitary disease such as adrenal insufficiency, ACTH-dependent conditions such as Cushing’s disease (pituitary source) or Cushing’s syndrome (ectopic source), and ACTH-independent conditions such as Cushing’s syndrome (adrenal source)Oral dose of 30 mg/kg metyrapone with snack at midnightCollect cortisol and ACTH at 8 a.m. on the morning after the metyrapone dose
ACTH = adrenocorticotropic hormone; CRH = corticotropin-releasing hormone; IM = intramuscular; IV = intravenous.

Normal findings

(Method: Immunochemiluminescent assay) Cortisol
TimeConventional UnitsSI Units (Conventional Units × 27.6)
8 a.m.
Birth–11 yr10–340 mcg/dL276–9384 nmol/L
12–18 yr10–280 mcg/dL276–7728 nmol/L
Adult/older adult5–25 mcg/dL138–690 nmol/L
4 p.m.
Birth–11 yr10–330 mcg/dL276–9108 nmol/L
12–18 yr10–272 mcg/dL276–7507 nmol/L
Adult/older adult3–16 mcg/dL83–442 nmol/L
Long-term use of corticosteroids in patients, especially older adults, may be reflected by elevated cortisol levels. ACTH Challenge Tests
ACTH (Cosyntropin) Stimulated, Rapid TestConventional UnitsSI Units (Conventional Units × 27.6)
BaselineCortisol greater than 5 mg/dLGreater than 138 nmol/L
30- or 60-min responseCortisol 18–20 mcg/dL or incremental increase of 7 mcg/dL over baseline value497–552 nmol/L or incremental increase of 193.2 nmol/L over baseline value
Corticotropin-Releasing Hormone Stimulated TestConventional Units
SI Units (Conventional Units × 27.6)
Cortisol peaks at greater than 20 mcg/dL within 30–60 minGreater than 552 nmol/L
SI Units (Conventional Units × 0.22)
ACTH increases twofold to fourfold within 30–60 minTwofold to fourfold increase within 30–60 min
Dexamethasone Suppressed Overnight TestConventional UnitsSI Units (Conventional Units × 27.6)
Cortisol less than 1.8 mcg/dL next dayLess than 49.7 nmol/L
Metyrapone Stimulated Overnight TestConventional Units
SI Units (Conventional Units × 27.6)
Cortisol less than 3 mcg/dL next dayLess than 83 nmol/L
SI Units (Conventional Units × 0.22)
ACTH greater than 75 pg/mLGreater than 16.5 pmol/L
SI Units (Conventional Units × 28.9)
11-deoxycortisol greater than 7 mcg/dLGreater than 202 nmol/L


Cortisol (hydrocortisone) is the predominant glucocorticoid secreted by the adrenal glands in response to pituitary adrenocorticotropic hormone (ACTH). Cortisol is responsible for a number of regulatory functions which include stimulation of gluconeogenesis (generation of glucose from amino acids by the liver), breaking down fats to generate energy, acting as an insulin antagonist by increasing glucose levels, responding to stress, and suppressing inflammation. Measuring levels of cortisol in blood is the best indicator of adrenal function. Cortisol secretion varies diurnally, with highest levels occurring on awakening and lowest levels occurring late in the day, although bursts of cortisol excretion can occur at night. This pattern may be reversed in individuals who sleep during daytime hours and are active during nighttime hours. Cortisol and ACTH test results are evaluated together because they each control the other’s concentrations (i.e., any change in one causes a change in the other). ACTH levels exhibit a diurnal variation, peaking between 6 and 8 a.m. and reaching the lowest point between 6 and 11 p.m. (See monograph titled “Adrenocorticotropic Hormone [and Challenge Tests].”) Salivary cortisol levels are known to parallel blood levels and can be used to screen for Cushing’s disease and Cushing’s syndrome.

There are three main conditions that can result from an imbalance in cortisol levels. Cushing’s syndrome is a complex condition that results from excessive levels of cortisol, regardless of the cause. Cushing’s disease is a condition in which the pituitary gland releases too much ACTH resulting in overproduction of cortisol. Addison’s disease is caused by failure of the adrenal glands to produce cortisol.

This procedure is contraindicated for

  • high alertPatients with suspected adrenal insufficiency should not undergo the metyrapone stimulation test because it may induce an acute adrenal crisis, a life threatening condition, in patients whose adrenal function is already compromised.


  • Detect adrenal hyperfunction (Cushing’s syndrome)
  • Detect adrenal hypofunction (Addison’s disease)

Potential diagnosis

The dexamethasone suppression test is useful in differentiating the causes for increased cortisol levels. Dexamethasone is a synthetic steroid that suppresses secretion of ACTH. With this test, a baseline morning cortisol level is collected, and the patient is given a 1-mg dose of dexamethasone at bedtime. A second specimen is collected the following morning. If cortisol levels have not been suppressed, adrenal adenoma may be suspected. The dexamethasone suppression test also produces abnormal results in patients with psychiatric illnesses.

The corticotropin-releasing hormone (CRH) stimulation test works as well as the dexamethasone suppression test in distinguishing Cushing’s disease from conditions in which ACTH is secreted ectopically. In this test, cortisol levels are measured after an injection of CRH. A fourfold increase in cortisol levels above baseline is seen in Cushing’s disease. No increase in cortisol is seen if ectopic ACTH secretion is the cause.

The ACTH (cosyntropin)-stimulated rapid test is used when adrenal insufficiency is suspected. Cosyntropin is a synthetic form of ACTH. A baseline cortisol level is collected before the injection of cosyntropin. Specimens are subsequently collected at 30- and 60-min intervals. If the adrenal glands are functioning normally, cortisol levels rise significantly after administration of cosyntropin.

The metyrapone stimulation test is used to distinguish corticotropin-dependent (pituitary Cushing’s disease and ectopic Cushing’s disease) from corticotropin-independent (carcinoma of the lung or thyroid) causes of increased cortisol levels. Metyrapone inhibits the conversion of 11-deoxycortisol to cortisol. Cortisol levels should decrease to less than 3 mcg/dL if normal pituitary stimulation by ACTH occurs after an oral dose of metyrapone. Specimen collection and administration of the medication are performed as with the overnight dexamethasone test.

Increased in

  • Conditions that result in excessive production of cortisol.

  • Adrenal adenoma
  • Cushing’s syndrome
  • Ectopic ACTH production
  • Hyperglycemia
  • Pregnancy
  • Stress

Decreased in

    Conditions that result in adrenal hypofunction and corresponding low levels of cortisol.

    Addison’s disease Adrenogenital syndrome Hypopituitarism
Summary of the Relationship Between Cortisol and ACTH Levels in Conditions Affecting the Adrenal and Pituitary Glands
DiseaseCortisol LevelACTH Level
Addison’s disease (adrenal insufficiency)DecreasedIncreased
Cushing’s disease (pituitary adenoma)IncreasedIncreased
Cushing’s syndrome related to ectopic source of ACTH IncreasedIncreased
Cushing’s syndrome (ACTH independent; adrenal cancer or adenoma)IncreasedDecreased
Congenital adrenal hyperplasiaDecreasedIncreased

Critical findings


Interfering factors

  • Drugs and substances that may increase cortisol levels include anticonvulsants, clomipramine, corticotropin, cortisone, CRH, ether, fenfluramine, gemfibrozil, hydrocortisone, insulin, lithium, methadone, metoclopramide, mifepristone, naloxone, opiates, oral contraceptives, ranitidine, tetracosactrin, and vasopressin.
  • Drugs and substances that may decrease cortisol levels include barbiturates, beclomethasone, betamethasone, clonidine, desoximetasone, dexamethasone, ephedrine, etomidate, fluocinolone, ketoconazole, levodopa, lithium, methylpredniso-lone, metyrapone, midazolam, morphine, nitrous oxide, oxazepam, phenytoin, ranitidine, and trimipramine.
  • Test results are affected by the time this test is done because cortisol levels vary diurnally.
  • Stress and excessive physical activity can produce elevated levels.
  • Normal values can be obtained in the presence of partial pituitary deficiency.
  • Recent radioactive scans within 1 wk of the test can interfere with test results.
  • high alertMetyrapone may cause gastrointestinal distress and/or confusion. Administer oral dose of metyrapone with milk and snack.

Nursing Implications and Procedure

Potential nursing problems

ProblemSigns & SymptomsInterventions
Body image (Related to increased androgen production [virilism, hirsutism]; wasting of muscle and bone matrix; capillary fragility; purple striae; slender limbs; abnormal fat distribution [buffalo hump])Negative verbalization of altered physical appearance; preoccupation with physical body changes; distress and refusal to talk about changed appearance; negative verbalization about changes in appearance; using clothing to conceal body changesAssess the patient’s perception of physical changes; note the frequency of negative comments about changed physical state; assist in the identification of positive coping strategies to address changed physical appearance; provide reassurance that changes in physical appearance will improve as hormones return to normal level; provide a referral to local support groups
Infection risk (Related to impaired immune response secondary to elevated cortisol level)Delayed wound healing; inhibited collagen formation; impaired blood flow to edematous tissues; symptoms of infection (temperature; increased heart rate; increased blood pressure; shaking; chills; mottled skin; lethargy; fatigue; swelling; edema; pain; localized pressure; diaphoresis; night sweats; confusion; vomiting; nausea; headache) Decrease exposure to environment by placing the patient in a private room; monitor and trend vital signs; monitor and trend laboratory values that would indicate an infection (white blood cells [WBC], C-reactive protein [CRP]); promote good hygiene; assist with hygiene as needed; administer prescribed antibiotics, antipyretics; provide cooling measures; administer prescribed intravenous fluids; monitor vital signs and trend temperatures; encourage oral fluids; adhere to standard or universal precautions; isolate as appropriate; obtain cultures as ordered; encourage use of lightweight clothing and bedding
Fluid volume (Related to sodium and water retention secondary to elevated cortisol levels)Overload: Edema, shortness of breath, increased weight, ascites, rales, rhonchi, and diluted laboratory valuesRecord daily weight and monitor trends; record accurate intake and output; monitor laboratory values that reflect alterations in fluid status (potassium, blood urea nitrogen, creatinine, calcium, hemoglobin, and hematocrit, sodium); manage underlying cause of fluid alteration; monitor urine characteristics and respiratory status; establish baseline assessment data; assess and trend heart rate and blood pressure; assess for symptoms of fluid overload such as Jugular Venous Distention (JVD), shortness of breath, dyspnea, crackles; encourage low-sodium diet; administer prescribed diuretic; administer prescribed antihypertensive; elevate feet when sitting; monitor oxygenation with pulse oximetry
Injury risk (Related to poor wound healing; decreased bone density; capillary fragility)Easy bruising; blood in stool; skin breakdown; fracture; poor wound healing Assess for bruising; assess stool for occult blood; assess for skin breakdown; assess wound for healing progress; facilitate ordered bone density screening


  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assist in assessing for the amount of cortisol in the blood.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s endocrine system, as well as results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that multiple specimens may be required. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.
  • Drugs that enhance steroid metabolism may be withheld by medical direction prior to metyrapone stimulation testing.
  • Instruct the patient to minimize stress to avoid raising cortisol levels.


  • Potential complications:
  • Adverse reactions to metyrapone include nausea and vomiting (N/V), abdominal pain, headache, dizziness, sedation, allergic rash, decreased white blood cell count, or bone marrow depression. Monitor the patient for hypotension, rapid and weak pulse, rapid respiratory rate, pallor, and extreme weakness that may indicate the patient is in acute adrenocortical insufficiency (Addisonian crisis). Other signs and symptoms include cardiac arrhythmias, hypotension, dehydration, anxiety, confusion, impairment of consciousness, N/V, epigastric pain, diarrhea, hyponatremia, and hyperkalemia.

  • Have emergency equipment readily available.
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture. Collect specimen between 6 and 8 a.m., when cortisol levels are highest.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
  • Promptly transport the specimen to the laboratory for processing and analysis.


  • Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
  • Recognize anxiety related to test results, and offer support.
  • Observe/assess the patient who has been administered metyrapone for signs and symptoms of an acute adrenal (Addisonian) crisis which may include abdominal pain, nausea, vomiting, hypotension, tachycardia, tachypnia, dehydration, excessively increased perspiration of the face and hands, sudden and significant fatigue or weakness, confusion, loss of consciousness, shock, coma. Potential interventions include immediate corticosteroid replacement (IV or IM), airway protection and maintenance, administration of dextrose for hypoglycemia, correction of electrolyte imbalance, and rehydration with IV fluids.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.
  • Patient Education

    • Instruct the patient to resume usual medications, as directed by the HCP.
    • Discuss the implications of abnormal test results on the patient’s lifestyle.
    • Provide teaching and information regarding the clinical implications of the test results, as appropriate.
    • Assess the patient with regard to the effects of abnormal cortisol levels, and monitor blood glucose levels to identify hyperglycemia associated with elevated cortisol.
    • Educate the patient regarding access to counseling services.
    • Provide contact information, if desired, for the Cushing’s Support and Research Foundation (
    • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
    • Recognize anxiety related to test results and answer any questions or address any concerns voiced by the patient or family.
    • Teach patient to use devices that will decrease injury risk such as soft toothbrush or electric rather than steel blade razor.
  • Expected Patient Outcomes

    • Knowledge
    • States understanding that precautions should be taken with activity to prevent injury
    • States understanding of reporting difficulty breathing promptly for timely intervention and prevention of respiratory distress
    • Skills
    • Identifies and selects a diet that is high in fiber and drinks plenty of fluids to prevent constipation and potential GI bleed
    • Demonstrates performance of good personal hygiene including moisturizing of skin to prevent breakdown
    • Attitude
    • Complies with HCP’s recommendation to increase the intake of calcium and vitamin D
    • Complies with the request to maintain good personal hygiene including frequent hand hygiene

Related Monographs

  • Related tests include ACTH and challenge tests, angiography adrenal, chloride, CT abdomen, CT pituitary, DHEA, glucagon, glucose, glucose tolerance test, growth hormone, insulin, MRI abdomen, MRI pituitary, renin, sodium, testosterone, and US abdomen.
  • Refer to the Endocrine System table at the end of the book for related tests by body system.
Handbook of Laboratory and Diagnostic Tests, © 2013 Farlex and Partners