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Blood Tests




Blood Calcium (Ca+)

Plasma ACTH

Dexamethasone Suppression

Plasma Cortisol

Fasting Plasma Glucose

Plasma Renin Activity

HPA Axis Blood Test

Total Carbon-Dioxide Content

Insulin Tolerance

Two-Hour Post-Prandial Plasma Glucose

Blood tests: These involve a sterile needle inserted into the vein and blood withdrawn for examination.

Growth Hormone Testing has been moved to


For menstruating women, this test should be done 1 week before menstrual period. Otherwise, test may need to be repeated.


Normal values are:

Premenopausal women, 0.6 to 3ng/ml

Postmenopausal women, 0.3 to 8ng/ml

Men, 0.9 to 1.7ng,ml


High may indicate:

In women:


Cushing's syndrome




Menstrual irregularities


Polycystic ovaries


Stein-Leventhal Syndrome


Tumors of the ovaries or adrenal glands

In children:


Premature sexual development

In men:


Breast enlargement


Less-masculine voice



of the testicles


Low may indicate:

Decreased function of the ovaries or testicles


Taking these drugs may affect test results:

pituitary hormones


Blood Calcium (Ca+):

Tests for several things, such as blood-clotting deficiencies, bone disorders, endocrine disorders and more.


Normal values are:

Adults, 8.9 to 10.1mg/dl

Children who are rapidly growing, 23mg/dl


High may indicate:

Adrenal insufficiency

Excessive calcium intake


Kidney disease

Metastatic cancer

Multiple fractures

Multiple myeloma

Overuse of antacids, such as calcium carbonate

Paget's disease

Parathyroid tumors

Prolonged bed rest


Low may indicate:

Acute pancreatitis

Chronic kidney failure

Cushing's disease



Poor calcium absorption


Taking these drugs may affect test results:



Calcium Salts


Excessive vitamin D or derivatives


Oral contraceptives

Thiazide diuretics


More patient Information on Blood Calcium

Dexamethasone Suppression

This test helps to distinguish patients with excess production of ACTH due to pituitary adenomas from those with ectopic ACTH-producing tumors.

Patients are given dexamethasone, a synthetic glucocorticoid, by mouth every 6 hours for 4 days. For the first 2 days, low doses of dexamethasone are given, and for the last 2 days, higher doses are given. Twenty-four hour urine collections are made before dexamethasone is administered and on each day of the test. Since cortisol and other glucocorticoids signal the pituitary to lower secretion of ACTH, the normal response after taking dexamethasone is a drop in blood and urine cortisol levels. Different responses of cortisol to dexamethasone are obtained depending on whether the cause of Cushing's syndrome is a pituitary adenomas or an ectopic ACTH-producing tumor.

The dexamethasone suppression test can produce false-positive results in patients with depression, alcohol abuse, high estrogen levels, acute illness, and stress. Conversely, drugs such as phenytoin and phenobarbital may cause false-negative results in response to dexamethasone suppression. For this reason, patients are usually advised by their physicians to stop taking these drugs at least one week before the test.

Fasting Plasma Glucose (Fasting Blood Sugar)

HPA Axis Blood Test

The HPA axis blood test is a test that stimulates your hypothalmic pituitary axis. What happens is you go into the doctor (maybe fasting) and some base line blood samples are done. Then a drug, called cortrosyn, is injected, and your blood is taken 15, 30, 60 and maybe 90 minutes later to see how your pituitary responds to the cortrosyn, and if your adrenals respond to ACTH. The normal result is a rise in ACTH and a rise in cortisol. At 90 minutes, the levels should start to come back down, showing that the feedback loop is working.

Insulin Tolerance: This test helps to confirm the diagnosis of growth hormone deficiency or adrenocorticotropic-hormone deficiency; helps confirm the diagnosis of primary and secondary adrenal insufficiency; or identifies pituitary impairment.


You must fast for at least 12 hours prior to this test.


A blood sample is taken at the beginning of the test to establish normal values


An IV is inserted so that additional samples can be easily drawn


100U of regular insulin is injected intravenously over a 2 or 3 minute period.


Additional blood samples are drawn at intervals of 15, 30, 45, 60, 90 and 120 minutes.


Normal values are:

Glucose normally falls to 50% of the fasting level 20 to 30 minutes after insulin administration.  This stimulates a 10 to 20ng/dl increase over baseline values in both hGH and ACTH, with peak levels occurring 60 to 90 minutes after insulin administration


Abnormal may indicate:

Increase in human growth hormone (hGH) of less than 10ng/dl suggests hGH deficiency

Increase in ACTH levels below 10ng/dl suggests adrenal insufficiency


Taking these drugs may affect test results:



Calcium gluconate




pituitary-based drugs





Patient Information of Insulin Tolerance Tests


Plasma ACTH (Plasma Adrenocorticotropic Hormone)

Plasma Cortisol

Plasma Renin Activity (PRA Test)

Total Carbon-Dioxide Content (CO2)

Two-Hour Post-Prandial Plasma Glucose (2-Hour Post-Prandial Blood Sugar)

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