oxygenSaturation: HealthKit quantity type
HKQuantityTypeIdentifierOxygenSaturation · read from Apple’s documentation on 2026-10-02
HKQuantityTypeIdentifier.oxygenSaturation (Objective-C HKQuantityTypeIdentifierOxygenSaturation) is a HealthKit quantity type in Apple's "Vital signs" group. Apple's abstract: “A quantity sample type that measures the user’s oxygen saturation.” Apple's discussion says its samples use percent units and measure discrete values, so in HKStatisticsQuery it takes .discreteAverage, .discreteMin or .discreteMax. It is available from iOS 8.0 and watchOS 2.0. This site's verified cross-platform matrix pairs it with OxygenSaturationRecord on Android Health Connect in its Blood oxygen row, with the caveat “The type existing doesn't mean data exists — SpO2 is device-gated, and Apple Watch availability in the US has been subject to litigation.”
What Apple says oxygenSaturation is
A quantity sample type that measures the user’s oxygen saturation.
Apple’s abstract, quoted from its oxygenSaturation reference page, read 2026-10-02. Apple’s discussion of the type runs 26 words.
- Swift
HKQuantityTypeIdentifier.oxygenSaturation- Objective-C
HKQuantityTypeIdentifierOxygenSaturation- Family
HKQuantityTypeIdentifier- Apple's topic group
- Vital signs
- Group page
- Vital signs
- Apple's reference
- oxygenSaturation on developer.apple.com
Availability
The versions Apple’s documentation data gives for oxygenSaturation, platform by platform, as read on 2026-10-02.
| Platform | Introduced | Deprecated |
|---|---|---|
| iOS | 8.0 | — |
| iPadOS | 8.0 | — |
| Mac Catalyst | 13.0 | — |
| macOS | 13.0 | — |
| visionOS | 1.0 | — |
| watchOS | 2.0 | — |
The rest of that release: HealthKit Types Introduced in iOS 8.
Sum or average, and in which units
Apple states both of these in the prose of the type’s discussion, not as properties, so they are derived from Apple’s sentence and the sentence is shown with each.
Aggregation style
discrete — in an HKStatisticsQuery, use .discreteAverage, .discreteMin or .discreteMax. Apple’s sentence:
These samples use percent units (described in ) and measure discrete values (described in ).
Unit family
percent — every type in this family is on the HKUnit reference.
Apple states it in the same sentence as the aggregation style, quoted above.
Empty parentheses and a dangling “described in” mark links in Apple’s sentence to other documentation pages: the generator keeps the sentence’s text, not its links, and the quote is left as stored rather than repaired.
Can apps write oxygenSaturation?
Apple’s documentation for oxygenSaturation does not state that its samples are read-only. Apple states read-only status only in prose, and its silence is not a statement either way, so this page makes no claim that apps can save it.
On Android Health Connect
The verified cross-platform matrix pairs oxygenSaturation with OxygenSaturationRecord in its Blood oxygen row.
The type existing doesn't mean data exists — SpO2 is device-gated, and Apple Watch availability in the US has been subject to litigation. Verify current status.
The metric guide for this row: Blood oxygen on every platform.
Questions
- Should I sum or average oxygenSaturation in HealthKit?
- Average it, or take its minimum or maximum — do not sum it. Apple's documentation for oxygenSaturation describes it as measuring discrete values, so an HKStatisticsQuery over it takes .discreteAverage, .discreteMin or .discreteMax. Apple's sentence, as read on 2026-10-02: "These samples use percent units (described in ) and measure discrete values (described in )."
- Which unit family does Apple give oxygenSaturation?
- Percent. Apple's discussion of oxygenSaturation says its samples use percent units: "These samples use percent units (described in ) and measure discrete values (described in )."
- Does oxygenSaturation have a Health Connect equivalent?
- This site's verified cross-platform matrix pairs HealthKit's oxygenSaturation with OxygenSaturationRecord in its Blood oxygen row. The caveat recorded with that row: The type existing doesn't mean data exists — SpO2 is device-gated, and Apple Watch availability in the US has been subject to litigation. Verify current status.
- Which iOS version added oxygenSaturation?
- iOS 8.0. Apple's availability data for oxygenSaturation lists iOS 8.0, iPadOS 8.0, Mac Catalyst 13.0, macOS 13.0, visionOS 1.0 and watchOS 2.0.
Sources checked
- Apple — HKQuantityTypeIdentifier.oxygenSaturation · read 2026-10-02
- Apple — HKQuantityTypeIdentifier · read 2026-10-02
Apple’s abstract and sentences are quoted for identification; the page layout, the capsule and the cross-platform pairing are AIFitnessAPI’s. Generated from Apple’s documentation by scripts/fetch-healthkit-identifiers.mjs, not typed by hand — the same data as the full identifier table.