A glucose tolerance test checks how your body responds to sugar (glucose) and may be used to help diagnose diabetes.

You will be given a measured amount of glucose to drink. Blood samples will be taken before and at intervals after the drink to measure your blood sugar levels.

What to expect

• You will have a blood test before drinking the glucose
• You must drink the glucose within 5 minutes
• Further blood samples will be taken over 2 hours
• The test may last up to 3 hours (or longer for extended testing)

Before the test

• Eat a normal diet for 3 days before the test
• Do not eat after midnight before the test
• You may drink water only on the morning of the test
• Do not smoke before or during the test
• Take your usual medication unless told otherwise

This test measures how your body regulates growth hormone after taking glucose.

Normally, drinking glucose should reduce the level of growth hormone in the blood. If this does not happen, further tests may be required.

What to expect

• You will drink a glucose solution
• Blood samples will be taken over a 2-hour period
• The test may be extended to 4 hours if needed

Before the test

• Eat a normal diet for 3 days before the test
• Do not eat after midnight before the test
• Water only on the morning of the test
• Take usual medication unless instructed otherwise

This test checks whether your adrenal glands are producing enough steroid (cortisol) hormones.

You will be given an injection of a synthetic hormone (Synacthen), which stimulates your adrenal glands. Blood samples are taken to measure your response.

What to expect

• A blood sample is taken before the injection
• You will receive a Synacthen injection
• A second blood sample is taken 30 minutes later
• In some cases, an additional sample may be taken after 60 minutes

The test usually lasts 30–90 minutes.

Before the test

• You may eat breakfast and take usual medication unless told otherwise
• If you take steroid tablets (such as prednisolone or hydrocortisone), do not take them on the morning of the test
• Bring your medication with you to take after the test

This test measures levels of 17-hydroxyprogesterone (17 OHP) to check if your adrenal glands are producing excess hormones.

It can help diagnose rare endocrine conditions that may affect the menstrual cycle, skin or hair growth.

What to expect

• A blood sample is taken before the injection
• You will receive a Synacthen injection
• A second blood sample is taken 60 minutes later

The test takes around 1 hour.

Before the test

• You may eat and take medication as normal unless advised otherwise
• If you take steroid medication, do not take it on the morning of the test

Risks

• No side effects are expected from a single dose
• There is a very small risk of an allergic reaction
• Tell staff if you have asthma or a history of severe allergies

This test checks whether your adrenal glands are producing too much cortisol.

You will take a steroid tablet (dexamethasone) the night before your blood test. This should normally reduce cortisol production.

What to expect

• Take dexamethasone at 11pm the night before
• Attend for a blood test between 8am and 9am the next morning
• You may be asked to provide a urine sample before taking the tablet

Before the test

• Take your usual medication unless advised otherwise
• If you take steroid tablets, contact the team for advice

The test takes around 30 minutes at the hospital.

An adrenal incidentaloma is a swelling found in one or both adrenal glands during a scan carried out for another reason.

Most are benign (non-cancerous), but further tests are needed to confirm this.

What tests may be required

Hormone tests

• 24-hour urine collection to measure hormone levels
• Blood test to measure cortisol after taking dexamethasone
• Additional blood hormone tests

Follow-up scans

• CT scan or MRI scan of the adrenal glands if required

These tests help determine whether the adrenal gland is producing excess hormones and whether further treatment is needed.