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7.12 Testosterone
The testosterone test measures the level of testosterone in blood. The pituitary gland releases luteinizing hormone (LH) that stimulates the release of testosterone by the adrenal glands, testes, and ovaries. Testosterone is unbound in blood, called free, or bound to the sex hormone binding globulin (SHBG) protein in blood.
Why the Test Is Performed
The test assesses for the underlying cause of infertility, erectile dysfunction, osteoporosis in men, precocious puberty (boys), hirsutism in women, irregular menstruation, and the treatment for prostate cancer.
Before Administering the Test
Assess if the patient:• Is taking birth control pills, digoxin, Aldactone, corticosteroids, testosterone, estrogen, barbiturates or seizure medication
• Has hyperthyroidism or hypothyroidism
• Is obese
How the Test Is Performed
A sample of blood is taken from the patient’s vein. The patient will experience a tight feeling when the tourniquet is tightened, a pinch or nothing at all when the needle is inserted into the vein, and pressure when a gauze pad is pressed against the insertion site to stop bleeding. It can take up to 10 minutes for bleeding to stop if the patient is taking anti- coagulants (aspirin, coumadin). A small bruise might appear at the insertion site, which could become swollen fol- lowing this test. This is called phlebitis. Applying a warm compress several times a day will reduce the swelling.
Teach the Patient
Explain why the sample is taken and that the healthcare provider may ask the patient to refrain from taking birth control pills, digoxin, Aldactone, corticosteroids, testosterone, estrogen, barbiturates, or seizure medication before the test.
Understanding the Test Results
The testosterone hormone test results are available in 2 days. The laboratory determines normal values based on calibration of testing equipment with a control test. Test results are reported as high, normal, or low based on the laboratory’s control test.
• Normal test results:
• Bound testosterone:
■ Men:
– Older than 19 years: 280 to 1080 ng/dL
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– 16 to 19 years: 250 to 910 ng/dL – 14 to 15 years: 170 to 540 ng/dL – 10 to 13 years: less than 300 ng/dL – 7 months to 9 years: less than 30 ng/dL
■ Women:
– Older than 16 years: less than 70 ng/dL – 14 to 15 years: less than 60 ng/dL – 10 to 13 years: less than 40 ng/dL – 7 months to 9 years: less than 30 ng/dL
• Unbound testosterone: 0.3 to 2 pg/mL
High levels may indicate testicular cancer, adrenal gland cancer, ovarian cancer, polycystic ovary syndrome (PCOS), or precocious puberty (boys).
Low levels may indicate Klinefelter syndrome, cirrhosis, alcohol abuse, testicular disorder, or pituitary gland damage.
Solved Problems
Adrenocorticotropic Hormone (ACTH) and Cortisol
7.1 What causes the release of cortisol?The hypothalamus releases corticotrophin-releasing hormone (CRH), which causes the pituitary gland to release the adrenocorticotropic hormone (ACTH). ACTH causes the adrenal gland to release cortisol. Cortisol increases blood pressure and glucose, and reduces the immune responses.
7.2 What is the relationship between ACTH and cortisol?
ACTH levels fall when cortisol levels rise, and ACTH levels rise when cortisol levels fall.
7.3 What does the adrenocorticotropic hormone test measure?
The adrenocorticotropic hormone test measures the level of ACTH in the blood.
7.4 Why is the adrenocorticotropic hormone test ordered?
To assess the function of the pituitary gland and the adrenal glands.
7.5 What should you assess before administering the adrenocorticotropic hormone test?
Assess the patient for conditions that might affect the test results: intoxication; pregnancy; menstruation;
emotional or physical stress or severe injury; whether the patient underwent a radioactive tracer medical test the week before the ACTH test; whether the patient is taking corticosteroids (acts like cortisol), amphetamines, insulin, lithium carbonate (which causes the release of cortisol); has eaten or drunk 12 hours before the test; or has exercised within the previous 12 hours.
7.6 What should you teach the patient about the adrenocorticotropic hormone test?
Do not exercise 12 hours before the test. Avoid stressful situations 12 hours before the test. Explain when and why the blood samples are taken, that there might be bruising if the ACTH and cortisol levels are high, and that the test cannot be taken if the patient is pregnant, menstruating, intoxicated, or if the patient has taken corticosteroids, amphetamines, insulin, and lithium carbonate. If the patient is taking these medications, then the patient must stop taking them for 2 days before the test.
The healthcare provider may ask the patient not to eat or drink anything 12 hours before the test.
The patient may be permitted to eat low-carbohydrate foods for two days before the test.
Overnight Dexamethasone Suppression Test
7.7 What does the overnight dexamethasone suppression test measure?
The overnight dexamethasone suppression test examines the patient’s cortisol level after dexamethasone is administered.
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7.8 What is dexamethasone?
Dexamethasone is medication similar to cortisol, in that dexamethasone signals the pituitary gland that there is a high level of cortisol in the blood, causing the pituitary gland to suppress the release of ACTH.
7.9 After dexamethasone is administered to the patient, what should happen to the cortisol level?
The cortisol level should be lower because there is no ACTH in the blood to signal the adrenal glands to release cortisol. If cortisol levels remain high, then this is a sign of Cushing’s syndrome, as a result of an adrenal gland tumor producing cortisol.
7.10 Why is the overnight dexamethasone suppression test ordered?
The overnight dexamethasone suppression test is ordered to assess the function of the adrenal glands and for Cushing’s syndrome.
7.11 What must be considered before administering the Overnight Dexamethasone Suppression Test?
Assess the patient for conditions that might affect the test results by preventing a decrease in cortisol levels:
• Severe obesity, pregnancy, dehydration, uncontrolled diabetes, severe weight loss, acute alcohol withdrawal, severe injury, stress
• Taking birth control pills, phenytoin (Dilantin), MAOIs, lithium, morphine, aspirin, barbiturates, methadone, diuretics, or Aldactone
Assess the patient’s metabolism:
• Some patients metabolize dexamethasone quickly, resulting in a lower than expected blood level when the blood specimen is taken.
• In this case, the healthcare provider will increase the dose of dexamethasone.
• The patient may be given up to eight doses of dexamethasone over two days.
The patient should refrain from taking birth control pills, phenytoin (Dilantin), MAOIs, lithium, morphine, aspirin, barbiturates, methadone, diuretics, or Aldactone 48 hours before the blood specimen is drawn.
7.12 What is an outward sign of a high ACTH and cortisol level?
A patient with a high ACTH and cortisol level may experience bruising.
7.13 What should you explain to the patient before administering the overnight dexamethasone suppression test?
Do not exercise 12 hours before the test. Avoid stressful situations 12 hours before the test. Explain when and why the blood sample is taken, that there might be bruising if the ACTH and cortisol levels are high, and that the test cannot be taken if the patient has taken birth control pills, phenytoin (Dilantin), MAOIs, lithium, morphine, aspirin, barbiturates, methadone, diuretics, or Aldactone. If the patient is taking these medications, the patient must stop taking them for 2 days before the test. Do not eat or drink 12 hours before the test
7.14 What might a high overnight dexamethasone suppression test result infer?
A high overnight dexamethasone suppression test result might infer Cushing’s syndrome, hyperthyroidism, uncontrolled diabetes, heart failure, heart attack, poor diet, fever, alcoholism, depression, anorexia nervosa, or lung cancer.
Aldosterone Test
7.15 What is the relationship between renin and aldosterone?
Kidneys release renin. Renin is a hormone that signals the adrenal glands to release aldosterone to control blood pressure and fluids and the balance of electrolytes by retaining fluid and sodium.
7.16 What do you expect the healthcare provider to order when the aldosterone test is ordered?
The aldosterone test is typically performed with the renin activity test.
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7.17 What might be an outward sign of high levels of aldosterone?
A patient who has muscle cramps, muscle weakness, tingling in the hands, or high blood pressure may have a high level of aldosterone.
7.18 Why is the aldosterone test ordered?
The aldosterone test is ordered to assess for an adrenal gland tumor, the cause of high blood pressure, the cause of a low potassium level in the blood, and for an overactive adrenal gland.
7.19 What special preparation is required before administering the aldosterone test?
There is no special preparation required for this test.
7.20 What would you expect the healthcare provider to do if the aldosterone test is abnormal?
If the test result is abnormal, the healthcare provider may order subsequent aldosterone tests. For subsequent aldosterone tests, the patient should:
• Refrain from eating natural black licorice two weeks prior to the test.
• Eat 3 grams per day of sodium for 2 weeks prior to the test.
• Avoid a low salt diet, since this increases aldosterone levels.
• Avoid a high salt diet, since this decreases aldosterone levels. Do not eat olives, soy sauce, pretzels, potato chips, canned soups, bacon, and vegetables.
• Know that he or she might be asked to stand, sit, and lie when the test is administered, since the patient’s position may affect the test results. Standing or sitting for 2 hours before the test increases the aldosterone level.
7.21 What might a high level of aldosterone indicate?
Primary hyperaldosteronism directly affects the adrenal glands and the renin activity test is low (Adrenal hyperplasia, Conn’s syndrome–adrenal gland tumor).
Secondary hyperaldosteronism does not directly affect the adrenal glands and the renin activity test is high (cirrhosis, heart failure, kidney disease, preeclampsia).
7.22 What might a low level of aldosterone indicate?
Addison’s disease.
Cortisol Test
7.23 What does the cortisol test measure?
The cortisol test determines the level of cortisol in blood.
7.24 What might a high level of cortisol infer?
A high level of cortisol might infer an adrenal gland tumor, overactive adrenal gland, Cushing’s syndrome, Cushing disease, adenoma, depression, severe liver disease, obesity, hyperthyroidism, severe kidney disease, surgery, or sepsis.
7.25 What might a low level of cortisol infer?
A low level of cortisol might infer Addison’s disease, shock, Sheehan’s syndrome, or autoimmune disease.
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