Apple Watch blood oximeter

Released: September 2020

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Apple's Blood Oxygen app enables users to measure the percentage of oxygen carried by red blood cells from one's lungs to the rest of one's body. 

Apple says its Blood Oxygen 'app measurements are not intended for medical use, including self-diagnosis or consultation with a doctor, and are only designed for general fitness and wellness purposes.' 


Research studies show pulse oximetry apps fail to measure blood oxygen levels accurately and are unreliable, especially when they’re low, resulting in questioning the need for wristwatch blood oxygen sensors.

A December 2022 class-action lawsuit filed in the Southern District of New York claims that Apple Watch's blood oximeter does not work as well for Black people, amounting to consumer fraud. 

'While traditional fingertip pulse oximeters are capable of measuring blood oxygen levels and heart rate, wrist-worn devices [..] determine heart rate, as blood oxygen measurements from the wrist are believed inaccurate,' the complaint states.

It goes on to say 'Algorithms designed for fingertip sensing are inappropriate when based on wrist measurements, and can lead to over 90% of readings being unusable'.


Most retail blood oximeters cannot be marketed as medical advices without US Food and Drug Administration (FDA) approval, meaning their accuracy can be tricky to determine

It is unclear why Apple has not been through the FDA's well-established testing process.

Operator: Apple
Developer: Apple

Country: USA

Sector: Health

Purpose: Measure blood oxygen

Technology: Sensor; Blood measurement algorithm
Issue: Accuracy/reliability; Appropriateness/need; Bias/discrimination - race, ethnicity

Transparency: Governance; Black box; Marketing


Legal, regulatory

Research, advocacy

News, commentary, analysis

Page info
Type: System
Published: December 2022
Last updated: January 2023