Recording pulse oximeter readings

A pulse oximeter uses light at the fingertip to estimate oxygen saturation and display a pulse rate. It is not a diagnosis and can be affected by cold fingers, movement, nail products, poor circulation or an ill-fitting device. A single unexpected result should be checked rather than interpreted alone.

The useful pattern includes the reading, pulse, time, activity, body position and symptoms such as breathlessness or chest discomfort. Your usual level may differ from another person’s, so a clinician should interpret changes in context.

Rest quietly, warm your hand and remove nail polish if it interferes. Place the device securely on a fingertip, keep still, and wait until the display stops changing. Record the result with the time and how you feel; repeat after a short pause if it seems out of keeping with your symptoms.

Use the same finger and device when possible, and take it to a [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) if you need help interpreting a trend. The [Pulse Oximeter](/technology/pulse-oximeter/) page explains the device itself.

Call emergency services for severe breathlessness, blue or grey lips, new confusion, fainting, severe chest pain or inability to speak in full sentences. Do not delay help because a device reading appears reassuring if you look or feel seriously unwell. Contact a clinician promptly for repeated concerning readings or worsening breathing.

Ask what range is usual for you, how often to record readings, which symptoms override the number, whether your device is suitable, and how quickly to report a sustained change. Show the complete log rather than one isolated result.