Tests for pituitary conditions

Basic blood tests

Initially, your GP may perform some basic pituitary hormone function tests. The hormones that can be tested via a simple blood test include: cortisol, thyroid, prolactin, oestrogen, testosterone and growth hormone.

If the results returned were showing out of normal range and the GP agrees, a referral to an endocrinologist would be the next step for more thorough investigations.

For information about private blood testing please click here.

More thorough investigation tests... The following lists all of the usual pituitary tests carried out, but please note that you might not require all of these tests.

Name of test: ACTH

What hormone does it test: Directly tests ACTH
The condition it tests for: Cushing’s (excess cortisol) or Hypoadrenalism (low cortisol)
How is the test given: Blood sample taken first thing in the morning
How might I feel: Normal blood test, but needs to be done at hospital
What do the results mean: Deficiency of ACTH; underactive pituitary; raised/over production
How often is the test done: When endocrinologist feels it is necessary

Name of test: Day curve

What hormone does it test: Cortisol
The condition it tests for: To assess adequate levels achieved pre- and post-medication for those taking hydrocortisone
How is the test given: Take your usual hydrocortisone doses, blood is taken several times a day
How might I feel: No side effects
What do the results mean: Shows under- or over-replacement with medication
How often is the test done: Varies depending on your clinic/consultant

Name of test: Dexamethasone Suppression

What hormone does it test: Cortisol
The condition it tests for: Excess cortisol production
How is the test given: Tablet taken at midnight; blood test the following morning
How might I feel: No side effects
What do the results mean: Normal individuals suppress cortisol levels
How often is the test done: Initially, to aid diagnosis

Name of test: FSH

What hormone does it test: Follicle stimulating hormone
The condition it tests for: Stimulates production of sperm in men and follicle development in the ovaries for women
How is the test given: Blood sample 
How might I feel: No side effects
What do the results mean: Depends on age and timing of menstrual cycle (pre/mid/post)
How often is the test done: Varies

Name of test: Glucose tolerance

What hormone does it test: Growth hormone
The condition it tests for: Acromegaly
How is the test given: After a sugary drink, bloods are taken at 30-minute intervals for 2 hours 
How might I feel: Nausea, headache (although not always)
What do the results mean: People with acromegaly do not suppress GH levels
How often is the test done: Initial diagnosis and for review purposes. Varies, depending on your clinic/consultant but at least annually when taking GH replacement

Name of test: IGF-1

What hormone does it test: IGF-1 levels in those on GH replacement
The condition it tests for: To monitor baseline and regular reviews for patients on replacement GH
How is the test given: Blood test
How might I feel: No side effects
What do the results mean: Guide to overall circulating levels of GH in the blood stream
How often is the test done: To assess pituitary function and diagnosis of GH deficiency

Name of test: Insulin stress test/Insulin tolerance test

What hormone does it test: Gold Standard to assess pituitary function for cortisol and GH
The condition it tests for: To assess correct levels of cortisol and GH
How is the test given: After an injection of insulin, blood is taken every 30-minutes for 2 hours
How might I feel: Because blood sugar is lowered, you may feel dizzy and nauseous, sweaty, clammy, disorientated, heart racing. These effects are short-acting.
What do the results mean: Lowering blood sugar causes stress and body should respond by secreting cortisol and GH
How often is the test done: Diagnosis of GH deficiency. Post-operative: to assess pituitary function.

Name of test: LH

What hormone does it test: Luteinising hormone
The condition it tests for: Acts on testes in men to stimulate testosterone and on the ovaries in women to stimulate oestrogen
How is the test given: Blood test
How might I feel: No side effects
What do the results mean: see FSH
How often the test is done:

Name of test: Oestrogen

What hormone does it test: Oestrogen (females)
The condition it tests for: 
How is the test given: Blood test
How might I feel: No side effects
What do the results mean: see: FSH
How often is the test done: 

Name of test: Synacthen (stimulation test)

What hormone does it test: Cortisol
The condition it tests for: Low levels of cortisol
How is the test given: An intravenous injection, then a blood test
How might I feel: Some patients experience slight feeling of sickness, flushing of their face and a faster heartbeat. These are only brief and will have disappeared by the end of the test.
What do the results mean: Poor response shows cortisol deficiency
How often is the test done: Varies (usually 6-monthly or annually) dependent on individual circumstances   Please note: for patients with symptoms that may suggest cortisol deficiency that a ‘pass’ on a SST, may not always mean that cortisol deficiency is excluded, and that with persisting symptoms, referral to an endocrinologist is recommended, where testing may be carried out with alternatives such as the glucagon test or insulin stress test.

Name of test: Testosterone

What hormone does it test: Testosterone (in males)
The condition it tests for: 
How is the test given: Blood test (morning 9:00am sample is most accurate)
How might I feel: No side effects
What do the results mean: see: Diagnosis of deficiency
How often is the test done: For diagnosis and ongoing monitoring

Name of test: Water deprivation

What hormone does it test: ADH (anti-diuretic hormone). Serum and urine Osmolality (ability to concentrate urine)
The condition it tests for: Diabetes insipidus
How is the test given: Patient deprived of any fluids for approximately 8 hours. Blood is taken, weight checked and urine tested at regular intervals.
How might I feel: If you have DI, this test can be very uncomfortable as you cannot drink anything
What do the results mean: Specialist interpretation required
How often is the test done: For diagnosis only