Pituitary Innovation and Teaching


Blood tests || Vision tests || Imaging || Other tests

Blood tests

Blood tests are done to check hormone levels and other things like a person’s blood type, blood chemistry or blood counts. They are done before visits with the neurosurgeon and endocrinologist, before surgery, right after surgery, and for follow-up visits.

Before surgery:

  • If possible, come to St. Michael’s Hospital’s blood lab for blood tests. Come between 7:30 a.m. and 9 a.m. since hormone levels vary at different times of the day. An appointment is not needed, but if you live too far away, you can do the blood tests at a location closer to where you live.

Blood tests will also be done during the pre-admission appointment, right after surgery and for follow-up visits with the doctor. These blood tests help doctors check hormone levels and how they might affect your body.

Since hormone levels vary over they day, for the best accuracy, the blood tests should be done at 8 a.m. If you are taking the hormone medicine Hydrocortisone (Cortef®), hydrocortisone, or prednisone, the blood tests should be done 24 hours after your last dose of medicine. This means, for instance, that if you are doing the blood test Monday morning, your last Hydrocortisone (Cortef®) pill should be Sunday morning, then you take the next pill  right after you do the blood test. If you have questions about your blood tests, ask your doctor.

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Vision tests

These tests are important to accurately measure vision and check the health of the nerves to the eyes. 

Visual field test

Prior to coming to the appointment at St. Michael’s, ask your eye doctor, family or referring doctor to arrange for a “visual field test” to check your peripheral (side) vision. The test, requires concentration, does not hurt, and requires that a button be pressed every time a flash of light appears in a screen.

After you have a visual field test, your neuro-ophthalmologist will decide if you will need more eye testing. The following are two other tests they may arrange for you.

Optical Coherence Tomography (OCT)

This is an ultrasound test to measure the thickness of the nerve in the back of the eye (i.e. optic nerves). This test can tell if the nerves of the eyes have ever been damaged.

The OCT may not be covered by provincial health insurance. Please ask your ophthalmologist for more information about the cost of an HRT.

Visual Evoked Potential

A Visual Evoked Potential test will help your doctors know if the nerves of your eyes have been damaged by the tumour. This test involves flashing a light in your eyes while a machine measures the amount of time it takes for your brain to record the visual signal caused by the flash of light. If the brain takes a long time to record the visual signal, this tells your doctor that there is damage to the nerves of your eyes. 

Preparing for a visit with the neuro-ophthalmologist:

  • Arrange for someone to drive you home from the appointment. The eye drops used during the visit will make it hard to focus.
  • Bring eyeglasses
  • Bring sunglasses to wear home after the test
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Magnetic Resonance Imaging Scan (MRI)

This test gives doctors pictures of the pituitary gland and surrounding brain. The test is often done in 2 steps. First one set of pictures is made and then right after, a second set is taken after injection of a dye into the vein through an IV (intravenous) line. This test is done before and after surgery and during the follow-up for years after surgery.

Computed Tomography Scan (“CT” or “CAT scan”)

Computed tomography (CT) is a test that combines X-rays and computer scans. The pictures provide very detailed pictures of the bones in the nose and the bottom of the skull to help provide accurate guidance during surgery. This CT scan should be done at St. Michael’s.

Note: If the MRI was done at a hospital other than St. Michael’s, make sure to bring a copy of the MRI (loaded on to a CD-ROM or DVD) to the appointment with the neurosurgeon or endocrinologist.

Other tests

Illustration of pituitary treatmentHormones affect many internal organs and how your body functions. This means your doctors may need you to have tests to check your:

  • heart (echocardiogram -ECG)
  • intestines (colonoscopy)
  • bones (bone mineral density for osteoporosis)
  • prostate (for men only)
  • sleep (sleep study).
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Page last updated: November 22, 2016