Overnight oximetry


​Overnight oximetry is a routine sleep study commonly used to test for obstructive sleep apnoea (OSA)

Enquiries & Appointments


Our Overnight oximetry locations

The Harley Street Clinic

The Harley Street Clinic

35 Weymouth Street W1G 8BJ London
The Lister Hospital

The Lister Hospital

Chelsea Bridge Road, SW1W 8RH London
London Bridge Hospital

London Bridge Hospital

27 Tooley Street SE1 2PR London
The Wellington Hospital

The Wellington Hospital

8A Wellington Place NW8 9LE London

What is an oximetry study for?

Sleep apnoea can be a serious condition causing you to stop breathing for periods while you sleep.

Your consultant may recommend an oximetry if they suspect you have a sleep-related breathing disorder such as sleep apnoea.

The test is done at home using a small monitor to measure your oxygen levels overnight.

Need to know

Oximetry is usually done in the comfort of your own home as you sleep. You'll need to wear a small oxygen monitor clipped to your finger and sometimes a tube (cannula) in your nose to measure your breathing.

Your consultant will explain how these work and show you how to use them correctly. They'll also let you know if you'll need to wear them for one or two nights.

Afterwards, you'll return the monitor to the hospital where your consultant can download the information that's been recorded. If a dip in your oxygen levels or pause in your breathing is shown, this may indicate that you have sleep apnoea.


Your consultant will explain the test and answer any questions you may have. They'll show you how the monitoring devices work and make sure you're comfortable with what you'll need to do at home.

Your consultant will also explain is there is anything specific you need to do to prepare for the test. This may include avoiding certain medications, caffeine, smoking or alcohol before bed.

After you return the monitor to the hospital, you'll return for a follow-up appointment to review the results with your consultant. They'll let you know if you need to be treated for sleep apnoea or if any further assessments or detailed sleep studies should be done to confirm your diagnosis.