Spirometer Hygiene: Preventing Cross-Contamination Between Tests

A spirometer sits between dozens of employees in a single testing day. Every maneuver pushes exhaled breath — and whatever it carries — through the sensor. Infection control in occupational spirometry isn't a side note to the test; it's a condition of running the program at all, and it's built into ATS/ERS testing standards for exactly that reason.

Why does spirometer cross-contamination matter?

Exhaled breath can carry respiratory droplets, and a flow sensor that isn't protected between subjects becomes a shared surface every employee breathes through. Bacterial and viral filters exist specifically to break that chain. The risk isn't theoretical for occupational programs — mobile testing puts a technician through a high volume of employees back-to-back, often in a compressed on-site window, which raises the stakes on getting the barrier right every single time, not most of the time.

What's the difference between a filter and a flowtube?

A bacterial/viral filter (BVF) sits between the employee's mouth and the spirometer's flow sensor, catching droplets and particulates before they reach the measuring element. A flowtube is the disposable sensor element itself on turbine or ultrasonic instruments — some systems combine both functions in one single-use component, others require a separate filter in addition to a disposable flowtube. Check the manufacturer's IFU for the specific instrument; treating a flowtube as a filter substitute (or vice versa) on a device that requires both leaves a gap in the barrier.

Single-use vs reusable: what actually gets reused safely?

Component	Reuse status	Between-employee handling
Bacterial/viral filter	Single-use, one per employee	Discard immediately after test
Flowtube/turbine sensor (disposable models)	Single-use, one per employee	Discard immediately after test
Mouthpiece	Single-use, one per employee	Discard immediately after test
Reusable flow sensor housing (non-disposable models)	Reusable across employees	Manufacturer-specified disinfection between subjects or per shift
Nose clips	Reusable across employees	Disinfecting wipe between subjects

What does a defensible between-employee protocol look like?

Attach a fresh filter (and flowtube, if the instrument uses a separate disposable sensor) before every employee, with no exceptions for a "quick retest" on the same person mid-session — a repeat maneuver still needs its own new sensor once the original has been breathed through and set aside. Wipe down anything the employee touched — nose clip, chair, instrument housing — before the next subject sits down. Log consumable lot numbers alongside the test record when your quality system calls for it, the same way you'd log a calibration check. The habit that actually holds up under a busy mobile-testing schedule is treating the filter change as part of the test sequence itself, not a step someone remembers when they have a spare minute.

What should the disinfection routine cover between shifts?

Filters and flowtubes handle the per-employee barrier, but the instrument itself — the housing, the display, the carrying case in a mobile van — still accumulates contact from technicians and, on some models, from employees steadying the unit during the maneuver. Follow the manufacturer's approved disinfectant list rather than whatever's in the cleaning cabinet; some solutions can degrade sensor components or housing materials over repeated use even when they're effective disinfectants elsewhere. At minimum, wipe down external touchpoints between testing blocks and do a fuller clean at the start and end of each testing day. For mobile programs running multiple sites in a week, that end-of-day clean also catches anything a single between-subject wipe would miss.

What happens when non-OEM consumables get substituted?

Beyond the infection-control gap, a non-OEM filter or flowtube can change the flow resistance the spirometer was calibrated against, which shifts your FVC and FEV1 readings in ways that are hard to catch after the fact. That's the same calibration-integrity issue covered in spirometer calibration syringe checks — the instrument's accuracy depends on the whole consumable chain matching what it was validated with, not just the syringe check passing that morning.

How Foster handles this

We stock genuine EasyOne and Benson consumables — filters, flowtubes, and mouthpieces — specifically because substitutions are the most common way a compliant program quietly stops being compliant. On multi-employee mobile testing days, our technicians carry enough single-use sensors for the full roster plus a margin, so a busy schedule never becomes the reason a filter gets reused. Instruments and consumables ship together from our spirometry equipment page, and our on-site technicians follow the same discard-and-replace discipline whether they're testing five employees or fifty during on-site occupational health testing.

FAQ

Can a spirometer filter be reused for the same employee later the same day?

No. Once a filter or flowtube has been breathed through, it's discarded — even for a same-day retest on the same person. Manufacturer instructions treat these as single-use per test session, not per employee-per-day.

Do reusable flow sensor housings need disinfection between every employee?

Yes, on instruments where the sensor housing itself (not just a disposable flowtube) contacts breath flow, the manufacturer's IFU specifies a disinfection step between subjects or at defined intervals — follow that schedule exactly rather than a general office-cleaning cadence.

Does a bacterial/viral filter replace the need for a disposable flowtube?

Depends on the instrument. Some spirometers combine filter and flow-sensing into one disposable component; others require both a separate filter and a disposable flowtube. Check the specific model's documentation — don't assume one covers the other.

Where should filter lot numbers get logged?

Alongside the test record and calibration-verification log for that day, the same documentation chain covered in occupational spirometry best practices. It matters most when a result gets contested months or years later.

What's the cost impact of proper single-use consumables on a large testing program?

It's a real line item, not a rounding error — but it's small next to the cost of a contested result or an infection-control incident tracing back to a reused sensor. Request current volume pricing through a quote for your program size.