How to perform an oscillometry test

As for other clinical tests, obtaining a reliable oscillometry measurement requires technicians to follow a specific testing sequence. This will ensure good, repeatable, and high-quality oscillometry testing, allowing the physician to use the results and provide an interpretation to the patient based on their status, history, symptoms, and other diagnostic tests and parameters.

The following instructions are based on the recently published “Technical Standards for Respiratory Oscillometry” document issued by the European Respiratory Society. G. King et al – European Respiratory Journal, 2020; 55: 1900753 – Technical standards for respiratory oscillometry

Before the measurement:

• Encourage the patient to stay relaxed and breathe as normal

• Anticipate they may experience a “gentle vibration” or “fluttering” during the test.

• Anticipate that the test will last approximately the time required to record 5 to 10 quiet breaths and that it will be repeated 3 times.

  • Perform the test with the patient correctly seated, with an upright posture with a very slight “chin-up” position.
  • Instruct the patient to grip the mouthpiece with teeth and lips firmly to avoid leaks and to keep the tongue relaxed and below the mouthpiece, avoiding blockage.
  • Finally, before starting the recording, support the patient cheeks, and the floor of the mouth with palm and fingers or demonstrate to the patient how to do it by himself.

Recommended position below:


Record at least 5 artifacts-free breaths once the patient is ready. Encourage the patient to breathe in a relaxed and stable manner during the measurement. RESTECH validated algorithms will analyze the data and exclude, in real time, breaths with cough, glottis closure, or irregular breathing. Onscreen results will be displayed only for artifacts-free breaths.

During the measurement inspect the value of CoV (coefficient of variability) of Rtot of all the accepted breaths and minute ventilation (Ve) displayed on the right part or the screen. Ensure that:

  • CoV Rtot is≤ 30%
  • Ve is ≤18 L/min

These criteria help verify that all artifacts have been excluded by the device, and data have been recorded while the patient breathes in a relaxed and stable manner. In RESMON PRO, the system indicates these conditions in RED if Ve or CoV of Rtot exceeds the specified limits.

RESTECH suggests to discard measurements presenting Within-measurement CoV of Rtot > 30% and/or Ve>= 18 L/min

Note:Ve is good synthetic indicator of patient quiet breathing as it is the product of Vt (Tidal Volume) x RR (Respiratory Rate

After completing the measurement, allow the patient to rest for 30-60 seconds. Then, repeat the procedure until three measurements have been collected.


QUALITY: At the end of the session, in the results screen, ensure that the “within-session” CoV% between the accepted measurements is, as recommended by the latest “2020 ERJ Technical Standards for Respiratory Oscillometry ” within 10% (adults) or within 15% (pediatrics, < 18 years of age).

As additional quality control verify that Ve < 18L/min, indicating a quiet breathing test
Resmon indicates it in RED both CoV and Ve if their values exceeds such limits


Onscreen results are provided after the session, including expected predicted values and upper/lower limits of normality. Detailed numerical and graphical clinical report are immediately available for download, printing and/or transfer at the end of the session.

Physicians can use this information alongside the patient’s clinical history, symptoms, and results from other diagnostic tests. Oscillometry aids in detecting the presence of central and/or peripheral obstruction, evaluating patient response to therapy, and identifying abnormalities present during normal tidal breathing. In cases of interpretative doubts, whenever possible, consider combining FOT and spirometry in line with medical response and clinical history.

How it works and what can measure

Read More

How do you perform an oscillometry test

Read More

How to evaluate the results of an oscillometry test

Read More