Where the PFT experts come together

PFT Sensor and Calibration Technology

The development of our TrueFlow™ and TrueCheck™ technology began with the invention of robust and unique flow sensors for spirometry and PFT devices. Today's technology makes lung function testing available to more people, providing early and accurate diagnosis of respiratory diseases.

TrueFlow™ Technology

TrueFlow™ eliminates problems associated with analog instruments for flow measurement like turbines and bodyplethysmographs and makes our products simple, efficient and accurate. It is the only technology proven to require no calibration over its lifetime.

TrueFlow™ is a resistance-free, contact-free and calibration-free measurement.

The basic measurement principle can be described as follows: two ultrasound signals are sent diagonally across the flow path. The signal that goes with the flow is accelerated, while the one that goes against the flow is decelerated. The difference between the two transit times represents the speed of the flow. If done correctly environmental factors cancel each other out in the process.

This basic measurement principle allows, in theory, for calibration-free measurement. Yet, we know from over 30 years of experience that many additional factors need to be considered to make an ultrasound system truly accurate and calibration-free; and we can prove it!

Today's TrueFlow™ technology is comprised of multiple, independent components that are individually optimized to work together to measure air flow consistently.

calibration free - TrueFlow - TrueCheck - ultrasound - spirometer - spriometry - NDD

Specialized design, high quality components, Swiss precision-manufacturing, alongside stringent quality-controls, enable our EasyOne® products to be completely calibration-free and to be used inside or outside the lab with pin-point accuracy.

We use fourth generation ndd transceiver cells (airflow optimized ultrasound) in combination with our proprietary digital nano Time Processing Unit (nTPU) designed for ultra-fast transit time measurements. This allows us to measure ultrasound transit times with an accuracy to within 1 ns (light travels at 30 cm per ns).

The Flow Tube and the Spirette are critical components of the TrueFlow™ system as they define the surface area of the flow (flow equals speed multiplied by surface area). They are manufactured in compliance with the highest quality standards and under strict quality control.

Consideration of all these aspects makes for first-rate spirometry and PFT devices which remain reliably accurate without calibration. This permits clinicians to focus on their patients rather than on maintaining the quality of the equipment.

calibration stability - EasyOne - NDD - Respire Care - spirometry - spirometer - calibration free
Skloot GS, Edwards NT, Enright PL; Four-year calibration stability of the EasyOne portable spirometer; Respire Care. 2010 Jul: Over 5,000 calibration-check results were accumulated from a total of 34 ndd spirometers during the period from 2003-2007.

TrueCheck™ Technology

Our patented TrueCheck™ system ensures correct gas analysis at all times. TrueCheck™ eliminates the need for gas-calibration as well as the need for an external DLCO simulator.

TrueCheck™ measures the sample-delay (using Signal Synchronization Technology), produces a gas concentration check and verifies the gas analyzer by performing a 5-point validation and linearization for each independent trial.

In order for a lung function test to be valid the gas concentration measurement needs to be aligned with the flow (signal synchronization). DLCO (Diffusion Capacity) and MBW (Multiple Breath Washout, N2) measurements are dependent on correct flow, volume and gas concentration. Variance in any of these values leads to significant errors, making traditional DLCO measurements extraordinarily difficult to control.

TrueCheck - DLCO - MBW - NDD - spirometry - spirometer

As a result such tests are performed in specialized labs only, which increases the cost of healthcare and limits the abilities of respiratory healthcare professionals to complete vital spirometry or PFT measurements.

Through the combination of TrueFlow™ and TrueCheck™ technology, we are able to remove all common sources of error, making the DLCO and MBW measurement robust and stable over the lifetime of the device. The combination of our high-quality materials, precision manufacturing process and proprietary technology produces spirometry and PFT equipment that offers value to healthcare professionals without compromising quality.

A research study found nearly 25 percent of the DLCO devices tested to be inaccurate - even directly after calibration. Our TrueCheck™ technology ensures 100 percent accurate measurement without calibration and completes quality control automatically.

long term stability of a portable DLCO - NDD - Spirometer - Spirometry

Laura Gochicoa-Rangel, Rogelio Pérez-Padilla, Luis Torre-Bouscoulet, et al.; Longterm stability of a portable DLCO instrument; ERS 2015, abstract Number 851919. Variability of the lung-diffusing capacity. Dash lines represent ±3 ml/min/mmHg from the mean as recommended by ATS/ERS 2005 standardization.

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