Rezpio and spirometry
Spirometry is the snapshot.
Rezpio is the movie in between.
Spirometry is the test your clinician already trusts. It is precise, objective, and central to how COPD and asthma are diagnosed and staged. Rezpio was designed from the start to sit alongside it, not to replace it, filling the long gaps between visits with a continuous, passive signal.
- 1.8M+ voice recordings
- Peer-reviewed research
- Class IIa SaMD pathway in progress
First, what spirometry actually measures
Four numbers that describe how well your lungs move air.
You blow, as hard and as long as you can, into a mouthpiece. A device called a spirometer records the shape and speed of that breath. From that single effort, clinicians read out several numbers, each one telling a slightly different part of the story.
FEV1
Forced Expiratory Volume in 1 secondHow much air you can force out of your lungs in the first second of a hard breath out. Lower values suggest narrower or obstructed airways.
FVC
Forced Vital CapacityThe total amount of air you can force out after taking the deepest breath possible. It captures overall lung capacity available on demand.
FEV1 / FVC ratio
The obstructive-disease indicatorThe proportion of your total forced breath that comes out in that first second. A reduced ratio is the classic signature clinicians use to identify obstructive conditions such as COPD and asthma.
PEF
Peak Expiratory Flow (peak flow)The fastest speed of a hard breath out. Simpler than full spirometry and often tracked at home with a handheld peak flow meter, once or twice a day, to monitor asthma control.
Why clinicians trust it
Spirometry is the gold standard, and it should stay that way.
International guidelines are built around it. COPD severity is graded using GOLD staging, which uses FEV1 (as a percent of predicted) to place a patient in one of four severity groups. Asthma is assessed and stepped through therapy using GINA guidance, which likewise leans on spirometry and peak flow to confirm variable airflow limitation.
These tests are objective, reproducible, and directly tied to decades of outcomes data. Any serious respiratory product has to respect that.
- GOLD staging (COPD)
Global Initiative for Chronic Obstructive Lung Disease. Uses FEV1 % predicted (GOLD 1–4) alongside symptom and exacerbation history to guide therapy.
- GINA staging (asthma)
Global Initiative for Asthma. Uses spirometry and peak flow variability to confirm diagnosis and to step controller therapy up or down.
The core argument
A snapshot every few months. A signal every day.
Spirometry, done in clinic, is precise and objective, but it happens rarely. Home peak flow adds one or two readings a day if the patient is diligent. In between, the picture goes dark. That dark space is exactly where exacerbations quietly build.
The snapshot
- Precise and objective, the reference standard.
- In-clinic spirometry: typically every 3–12 months.
- Home peak flow: once or twice a day, when remembered.
- Requires effort: a forced maximal breath, correctly performed.
- Directly tied to GOLD and GINA staging decisions.
The movie in between
- Continuous, all day, every day the clip is worn.
- Passive: captured during ordinary speech, no test to perform.
- Trends across weeks, so subtle deterioration becomes visible.
- Not a diagnostic reading, a supporting trajectory.
- Designed to hand back to the clinician at the next spirometry visit.
One image
Twelve weeks of care, drawn honestly.
Two spirometry visits, a scattering of home peak flow readings on the days a patient remembered, and, underneath, Rezpio's continuous coverage across every one of those days. The visits stay exactly where they are. The dark space between them stops being dark.
Illustrative. Actual spirometry cadence, peak flow adherence, and Rezpio wear time will vary by patient. The point of the diagram is the shape of coverage, not specific values.
For clinicians
Both data types, on the same timeline.
The Rezpio Clinical Portal supports manual entry of spirometry and peak flow readings taken in your workflow, from an in-clinic PFT, a home peak flow diary, or a patient-reported number. Those values sit on the same timeline as the Rezpio voice-biomarker trajectory.
That means at each visit, you can see the objective spirometry point you took today, the last one you took months ago, and how Rezpio's between-visit trend moved during that gap. Correlate the trajectory with the reference test. Keep the reference test as the reference.
- Manual PFT / peak flow entry
Enter FEV1, FVC, FEV1/FVC, and PEF from any source. Date-stamped and attributed.
- Combined timeline view
Spirometry points and voice-biomarker trajectory on a shared axis.
- Between-visit trend
See what happened in the weeks between two spirometry points, not just the two endpoints.
Built with the clinic in mind
Rezpio was built by people who respect spirometry. The point was never to replace the reference test, it was to give clinicians a signal in the months when there wasn't one.