What should you know about a Lifebox pulse oximeter?

The device uses light passing through the fingertip to estimate oxygen saturation and pulse. Cold hands, movement, nail products, poor circulation or an incorrect fit can make a reading unreliable. A number is not a diagnosis and should be considered with breathing, colour, alertness and the reason you are monitoring. Some lung or heart problems can cause serious symptoms even when a home reading seems reassuring.

Rest for a few minutes, warm your hand, remove dark nail polish if possible, and place the device securely on a finger. Keep still while the display settles, then record the reading with the time and your symptoms. Repeat a surprising result once after checking the fit, but do not delay help for severe symptoms. A [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) can help decide whether home monitoring is suitable.

Seek urgent help for severe breathlessness, blue or grey lips, chest pain, confusion, collapse, or unusual drowsiness, regardless of the display. Contact a clinician promptly for worsening breathing, persistent low readings, or a clear change from your usual level. Take the device and your recorded readings if you attend for assessment.

Ask whether you need monitoring, how often to check, what range is usual for you, how to confirm a doubtful reading, and which symptoms should override the device.