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Hydrocortisone Day Curve - 4 point

Patient information A-Z

Why am I having this test?

Your doctor has referred you to have Hydrocortisone Day Curve test to check that your Hydrocortisone dose is appropriate. Cortisol is the body’s natural steroid hormone, it is released from the adrenal glands which sit just above the kidneys. It is a vital hormone that is responsible for enabling the body to respond to stress and illness and also

regulates the immune system, blood pressure, and blood sugar levels.

Cortisol production is controlled by the pituitary gland which is a tiny pea sized gland just underneath the brain. A problem with either the pituitary or adrenal glands can cause low cortisol levels. As your body does not produce enough cortisol of its own, you are taking replacement hydrocortisone in tablet form. This test is to ensure you are taking the right dose, at the right time, for your needs.

Do I need to prepare for the test?

You do not need to fast for this test (unless indicated on your appointment letter).Please DO NOT take your Hydrocortisone on the morning of the test but bring your Hydrocortisone and any other medications you will need for the day with you.


If you are using the oral contraceptive pill, or oral HRT you will need to stop them for six weeks prior to your test as they can affect results. If you are using an HRT patch you may continue to do so.

If you are stopping the contraceptive pill you must use an alternative contraceptive to avoid pregnancy.

What happens during the test?

You will need to arrive at the Endocrine Investigation Unit by 9am. Your blood will be taken using a butterfly needle to assess your cortisol level at four time points throughout the day.

How long will the test take?

You will need to have blood taken in the Unit at three separate times. Usually 09:00, 12.30 and 16.30, but this will depend on your particular dosing regimen. We will need to take the blood for the midday and afternoon samples before you take your dose of Hydrocortisone. The exact timings will be discussed with you when you have your first sample taken. Between these times you are free to leave the Unit or Hospital if you wish.

Will I experience any side effects?

The test has no common side effects.

When will I get my results?

Results cannot be given out over the telephone and will be discussed at your next clinic appointment.

Any other questions?

Please contact the endocrine unit on 01223 217848. Monday to Friday – 09:00 to 17:00.

The timing of the test is important so please attend at the time specified on your appointment letter. If you are unable to attend your appointment please contact the Endocrine unit to re-arrange it.

General Information

Discounted parking is available for patients attending clinic appointments over three hours duration. Please present your appointment letter to receive this.

Food and drink - there is a coffee shop in the treatment centre atrium and further food and drink facilities in the main hospital concourse.

Privacy & dignity

Same sex bays and bathrooms are offered in all wards except critical care and theatre recovery areas where the use of high-tech equipment and/or specialist one to one care is required.

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

Other formats

Help accessing this information in other formats is available. To find out more about the services we provide, please visit our patient information help page (see link below) or telephone 01223 256998.

Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151