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CPAPClarity.com

Wellue O2 Ring · OxySmart · O2Ring S · O2Ring 5103 · Checkme O2 Max

See your overnight SpO2 next to your CPAP

CPAP Clarity reads your Wellue ViHealth CSV and computes AASM-style ODI at both 3 and 4 percent thresholds, mean and minimum SpO2, time below 88 percent, and motion-aware coverage. All of it lines up next to your CPAP AHI on the same night.

View the Oxygen dashboard

Can the O2 Ring screen for sleep apnea?

More legitimately than a smartwatch or a sleep-stage wearable, but still not as a substitute for a sleep study. Overnight pulse oximetry has decades of clinical validation as a screening tool specifically for sleep-disordered breathing. The Hang et al. 2015 BMC Pulmonary Medicine study reported around 87 to 90 percent sensitivity and 86 to 93 percent specificity for detecting moderate-to-severe OSA using ODI derived from overnight oximetry.

The mechanism is direct: an obstructive or central apnea blocks airflow, oxygen falls, and the pulse oximeter captures the dip. Snoring or partial obstruction without desaturation can slip through, and central sleep apnea with arousal but minimal desaturation can also be missed, so a clean ODI does not rule apnea out. A high ODI on a single clean night, on the other hand, is a meaningful signal.

If you are using the O2 Ring to screen yourself, pair the data with a validated questionnaire and a clinician conversation.

What CPAP Clarity reads from your O2 Ring

Overnight SpO2
Mean / Median

CPAP Clarity computes the mean and median oxygen saturation across the full recording. The mean is what most clinicians cite when they ask about your overnight oxygen.

ODI (3%)
Events per hour

Oxygen Desaturation Index at the AASM-recommended 3% threshold. Counts each time your SpO2 drops more than 3 percent below your stable overnight level and then recovers, divided by recording hours (gap-corrected for motion).

ODI (4%)
Events per hour

ODI at the AASM-acceptable 4% threshold. Most CPAP clinics in the United States still use the 4% rule. CPAP Clarity reports both so you have the number your clinician asks for.

Minimum SpO2
Lowest reading

The single lowest oxygen value during the recording, with the motion artifact filtered out. Useful for catching brief severe dips that the average hides.

Time below 88%
Minutes + percent

The total minutes your SpO2 sat below 88 percent (the CMS supplemental-oxygen threshold) and the percent of total recording time. A standard reporting line on clinical pulse oximetry studies.

Motion-Aware Coverage
Clean vs flagged seconds

Pulse oximeters drop and corrupt readings when you move. CPAP Clarity flags motion-saturated stretches and excludes them from ODI denominators rather than silently inflating events.

Baseline Calibration
Your stable overnight SpO2

The baseline is your typical stable oxygen level for the night. A reading counts as a drop when it falls more than 3 percent (or more than 4 percent) below that level, which lines the counts up with what the ViHealth app shows on your device.

CPAP Overlay
Same-night side by side

Every O2 Ring night joins by calendar date to your CPAP session. The dashboard shows AHI, leak, and usage hours alongside ODI3, ODI4, mean SpO2, and minimum SpO2 for the same night.

How the O2 Ring compares to other ways to track overnight oxygen

FeatureWellue O2 RingApple WatchHome Sleep Study
Continuous overnight SpO2Yes: ~4 second cadencePartial: Sampled, not continuousYes: Medical-grade continuous
ODI calculationYes: AASM 3% and 4%No: Not surfaced in Health exportYes: Gold standard
Minimum SpO2 + time below 88%Yes: Both reportedNo: Not in the export shapeYes: Clinical reporting standard
Sleep stagesNo: Not measuredYes: Movement-based estimateYes: EEG, AASM scored
Airflow and respiratory effortNo: Not measuredNo: Not measuredYes: Essential for apnea typing
FDA cleared as a pulse oximeterYes: Viatom 510(k) for SpO2Yes: Series 6+ SpO2 sensorYes: Medical-grade equipment
FDA cleared to diagnose apneaNo: Not a diagnostic deviceNo: Notification feature onlyYes: Standard of care

For overnight oxygen specifically, the O2 Ring is the closest consumer device to a clinical pulse oximeter. It does not provide airflow, respiratory effort, or sleep staging, so it cannot replace a sleep study. For tracking and follow-up, it is the most useful consumer signal a CPAP user can collect.

Which should you use?

Choose the O2 Ring if

you want overnight ODI and minimum SpO2 numbers your sleep physician will recognize. You already have a CPAP and want a second source of evidence on therapy effectiveness. You are screening yourself and want a real oximetry signal.

Choose Apple Watch if

you already wear one daily. You value sleep stages alongside spot SpO2. You want Apple's sleep apnea notification feature on Series 9 and later. You do not need overnight ODI as a primary metric.

Choose a sleep study if

you suspect untreated sleep apnea and need a diagnosis. Home oximetry is flagging a problem and you want medical-grade confirmation. Your physician needs the full airflow and respiratory-effort picture for a treatment decision.

What an abnormal night might look like

Representative example. Numbers below are illustrative, not a real user's data.

In a representative concerning night, the O2 Ring CSV might score ODI3 of 18.4 events per hour and ODI4 of 9.2 events per hour, with mean SpO2 of 93 percent, minimum SpO2 of 81 percent, and 22 minutes spent below 88 percent across a 7 hour 18 minute recording. The CPAP side of the same night might show AHI 2.1, median leak 5 L/min, and a 6 hour 50 minute usage block.

In this illustrative scenario, the two streams tell different stories. The CPAP scored a quiet night by its own metric (AHI under 5), but the oxygen channel did not. ODI3 of 18.4 sits in the moderate range under the AASM tiering, the minimum SpO2 of 81 percent is below the threshold most clinicians flag, and the 22 minutes below 88 percent is the line CMS uses for supplemental oxygen consideration. That kind of CPAP-clean / oxygen-abnormal split usually points at residual flow limitation the CPAP is not scoring, central events that are blocking airflow without triggering an obstructive label, or REM-clustered events the AHI denominator dilutes.

None of those numbers prove anything on their own. A persistent multi-week pattern of high ODI on clean-AHI CPAP nights is the kind of signal worth bringing to a sleep physician. A single night with an oximeter cap that slipped is not. Look for the pattern across at least two weeks of recordings before drawing conclusions.

Shopping for an O2 Ring?

The Wellue O2Ring is the recording ring this page is built around. It exports the overnight CSV CPAP Clarity reads.

Affiliate links. As an Amazon Associate I earn from qualifying purchases at no extra cost to you. Recommendations are based on editorial merit.

Overnight SpO2 and ODI tracking

Wellue O2Ring

Records SpO2 and pulse every few seconds all night and exports the CSV CPAP Clarity reads. FDA-cleared for at-home use and rechargeable.

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How to import your O2 Ring data

1

Record an overnight session on your ring

Wear the O2 Ring as you normally do. Keep the ring on for the full night so the recording covers the full window. The ring auto-starts when worn.

2

Export the night as a CSV from ViHealth

Open the ViHealth app on your phone, tap the night you want, then tap Share, then CSV. The app emails or AirDrops the file to your computer. Or, if you use Wellue's O2 Insight program on a computer, connect the ring over USB and grab the raw session files it saves; for the format current rings produce, those let CPAP Clarity read the ring's own counts.

3

Drop the file onto CPAP Clarity

Open the Oxygen page at /oximeter and drop the CSV or raw session file onto the import card. The whole parse runs in your browser. Nothing leaves your device.

Go to the Oxygen import page

Frequently Asked Questions

Can the Wellue O2 Ring screen for sleep apnea?

Overnight pulse oximetry has a long, validated history as a sleep apnea screening tool. A 2015 BMC Pulmonary Medicine study by Hang et al. reported about 87 to 90 percent sensitivity and 86 to 93 percent specificity for detecting moderate-to-severe OSA using ODI. The O2 Ring records the raw signal that ODI is calculated from. It is not a diagnostic device, and a clean ODI does not rule apnea out, but a high ODI is a meaningful signal to bring to a sleep physician along with a STOP-BANG score.

What is the difference between ODI 3% and ODI 4%?

Both numbers count oxygen desaturations per hour. The 3% rule counts every SpO2 drop of more than 3 percent below your stable overnight level; the 4% rule requires more than 4 percent instead. The AASM recommends the 3% threshold; most US clinics still report the 4% value because Medicare's hypopnea definition uses 4%. CPAP Clarity computes both. Your number will look higher under the 3% rule because more events qualify.

Which Wellue model does CPAP Clarity support?

Five models across five CSV shapes: the O2 Ring (6-column CSV from ViHealth), OxySmart (3-column fingertip clip CSV), O2Ring S (6-column with 12-hour AM/PM timestamps), O2Ring 5103 (4-column with day-first European date format), the Checkme O2 Max (same 6-column CSV as the O2 Ring, recognized by its filename), and the LOOKEE-branded O2Ring, which works through ViHealth or through Lookee's own app (the Lookee app writes its dates differently, and both formats import). The parser auto-detects the shape from the header row. There is also a second import format for the ring models: the raw session files Wellue's O2 Insight desktop program saves when you connect a ring over USB (named like 20260705220726, no file extension). For the format current rings produce, CPAP Clarity reads the ring's own drop counts and O2 Score straight from the file.

Does CPAP Clarity's drop count match my ViHealth app?

From the CSV, it is built to line up: your stable overnight SpO2 is the baseline, and a reading more than 3 percent (or more than 4 percent) below it counts as a drop, checked against real Wellue device reports. On typical nights the counts match the number on your device. On a very busy night the CSV count can read lower, because the ring computes its official count on the device itself from its own high-rate internal readings and the export keeps only a thinned-out sample, so fast repeated dips can merge; when the two differ, treat your app's number as the reference. To close that gap, import the raw O2 Insight session files instead: for the file format current rings produce, CPAP Clarity reads the ring's own counts and O2 Score straight from those and marks the night as coming from your ring. If a future firmware changes the format, the site falls back to computing from the readings rather than guessing at the ring's numbers.

Is my pulse oximetry data shared with anyone when I import it?

No. The CSV is parsed entirely in your browser. CPAP Clarity does not upload your SpO2 data to any server. Your readings are stored only in your browser's local IndexedDB, on the device you imported from. Clearing your browser data, or using the data hub at /data, removes them.

How is overnight ring pulse oximetry different from a sleep study?

A sleep study (in-lab polysomnography or a Type III home sleep test) uses a medical-grade pulse oximeter alongside airflow, respiratory effort, EEG, and EMG sensors. Sleep stages are clinically scored from EEG. The O2 Ring records only the oxygen and pulse channel. It is excellent at catching the desaturation pattern that goes with obstructive apnea, but it cannot stage your sleep or count specific apnea types. Use it as a screening or trend tool, not as a substitute for a study.

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