uk Health & medical scares

What to do if…
your lips or fingertips turn blue or a pulse oximeter shows unexpectedly low oxygen

Produced and maintained by PanicStation.org Published: 27 July 2026 Last reviewed: 16 August 2026 Editorial policy UK guide

Short answer

Call 999 immediately if the lips, tongue, face or skin suddenly turn blue or grey, particularly with breathing difficulty, chest pain, confusion, unusual drowsiness or collapse. If a pulse oximeter reading remains at 92% or below after one careful repeat and this is not within a clinician-agreed personal range, call 999. For a reading of 93% or 94%, a fall below the person’s normal level, or blue fingers or toes without emergency symptoms, get urgent clinical advice.

Do not do these things

Do not wait for a pulse oximeter reading before calling 999 for suddenly blue or grey lips, tongue, face or skin.
Do not keep retesting while the person is struggling to breathe, becoming confused, collapsing or getting worse.
Do not rely on a phone, smartwatch or fitness tracker instead of the person’s symptoms.
Do not use unprescribed oxygen or change prescribed oxygen settings unless a healthcare professional or personal emergency plan tells you to.
Do not drive yourself to A&E if you are seriously unwell or unsafe to drive.
Do not assume cold weather, nail products or a faulty device explain a persistent colour change or low reading.

What to do now

Call 999 if the lips, tongue, face or skin have suddenly turned blue or grey. Also call if there is severe difficulty breathing, gasping, choking, an inability to get words out, a tight or heavy chest, sudden confusion, unusual drowsiness, fainting or collapse. Call for a child who is limp, floppy or not responding normally.
If the person is unresponsive or not breathing normally, call 999, put the phone on loudspeaker and follow the call handler’s instructions, including instructions about CPR.
Stay with the person and tell the 999 call handler when the colour change or symptoms began, any pulse oximeter reading, relevant medical conditions, prescribed oxygen use and any clinician-set oxygen target you know about.
If there are no emergency symptoms and the concern is only an unexpected pulse oximeter result, sit still and repeat the measurement once. Warm a cold hand, remove nail varnish or a false nail if readily possible, fit the device securely as its instructions describe, keep the hand still and wait for the display to settle. Do not delay urgent help to troubleshoot the device.
If the repeated reading is 92% or below and this is not within the person’s usual clinician-agreed range, call 999. Call 999 regardless of the number if serious symptoms develop or the lips, tongue, face or skin suddenly turn blue or grey.
If the reading is 93% or 94%, remains below the person’s usual level or continues to fall, get urgent clinical advice. Call 111 in England, Scotland or Wales. In Northern Ireland, contact the person’s GP urgently or the GP out-of-hours service if the surgery is closed. If you are pregnant or have recently given birth, contact your maternity service or hospital urgently for a low or falling reading and follow its escalation advice. NHS England guidance treats a reading of 94% or below in pregnancy as needing immediate clinical review, so do not rely only on the general 111 route.
If only the fingers, toes, hands or feet are blue or grey and the person is breathing normally and alert, move out of the cold, warm them gently and get urgent clinical advice through the service for your UK nation. Call 999 if the colour spreads to the lips, tongue, face or skin, or emergency symptoms appear.
If the person uses prescribed home oxygen, follow their prescription and personal action plan. Do not alter the flow rate unless their plan, a healthcare professional or the emergency call handler directs this.
On brown or black skin, a blue or grey change may be easier to notice on the lips, tongue, gums, palms, soles or inside the eyelids. Do not let difficulty judging the colour delay help when symptoms are serious.

What can wait

You do not need to identify the cause, buy another monitor, collect repeated readings for hours, arrange routine tests or decide on long-term oxygen treatment now. Focus on emergency warning signs, one careful repeat measurement when safe, and contacting the appropriate urgent service.

Important reassurance

Cold hands, movement, nail coatings, poor circulation and incorrect sensor placement can affect a pulse oximeter result, so one unexpected number does not confirm a diagnosis. Pulse oximeters can also overestimate oxygen saturation in people with darker skin tones, which means a seemingly reassuring number should not override serious symptoms. Prompt assessment is the safest response to sudden blue or grey lips or skin, or a persistently low unexpected reading.

Scope note

This guide covers immediate first steps only. Finding the cause and deciding on further monitoring or treatment may require assessment by a healthcare professional.

Important note

This is general medical information, not a diagnosis or a substitute for individual advice from a doctor, nurse, emergency call handler or other qualified healthcare professional.

Additional Resources

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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