The new 2005 ATS/ERS Spirometry Standard is in effect and we want to highlight key changes to equipment and test procedures to keep you updated.

Equipment Performance Specifications: All are unchanged except for:

PEF: Accuracy + 10% of reading or + .40 L/sec, whichever is greater.

(used to be .20 L/sec). Precision: + 5% or 150ml

Quarterly Chart recorder s time scale to be checked and must fall within 2% of set speed (used to be 1%).

Calibration Definitions:

Calibration: The procedure for establishing the relationship between sensor-determined values of Flow and Volume and actual Flow and Volume.

Calibration Check: Validates that the device is within calibration limits (+ 3%). If check fails, a new calibration or maintenance procedure must be undertaken.

The 3 Liter calibration syringe must be accurate to + 15 ml or 0.5%.

Note: A dropped calibration syringe should be considered out of calibration until checked.

Calibration Check for Flow Spirometers:

Volume accuracy of the spirometer to be checked daily using a 3L syringe using 3 Flow ranges (between 0.5L/sec to 12L/sec i.e. 1 sec, 3sec and 6sec). Required accuracy is based upon the combined spirometer and syringe accuracy(+ 3% spirometer plus syringe accuracy of + 0.5 %, or a total of 3.5%). This results in an acceptability window of 3.10 L to 2.90 L.

This is a change from the old standard where only the spirometer accuracy of 3% was considered

Check Linearity of Spirometer Weekly:

This new procedure requires that a 3 liter syringe be used to deliver 3 constant flows at a low flow rate, 3 at mid-range flows, and 3 at high flows. All flows must result in 3 L readings with an accuracy of +3.5%.

Note: When using disposable sensors, a new sensor from the supply source should be tested each day as part of the calibration check.

Daily Calibration Check for Volume Spirometer:

Check volume using a single discharge of 3L. This may need to be repeated several times a day when testing high volumes of people and when the ambient temperature is changing.

Leak tests to be conducted daily. Accomplished by occluding the spirometer outlet and applying a constant positive pressure of 3cm/H2O). A volume loss of >30 ml after 1 minute indicates a leak.

Quarterly Range Calibration:

A volume calibration test must be completed over the entire spirometer range using 1 Liter increments.

Note: Spirometer accuracy must be maintained under BTPS conditions for up to 8 consecutive FVC maneuvers performed within a 10 minute period.

Graph Sizes:

These are now presented for computer screens and for hard copy records.

Computer Screens: Volume: 5mm/L, Flow: 2.5mm/L/sec, Time: 10mm/sec.

Hard Copy: Volume: 10mm/L, Flow: 5mm/L/sec, Time: 20mm/sec. The aspect ratios for Flow Volume Curves are 2 units of Flow to 1 unit of Volume.

The hard copy time requirements can be relaxed in that the time base can be reduced to 10mm/sec when a Flow-Volume curve accompanies the Time-Volume curve.

Test Procedure Updates:

  • Well fitting false teeth should not be removed.
  • Although not required, a nose clip is recommended.
  • It is recommended to sit for the test.
  • End of Test (EOT) for adults is 6 seconds with 1 second plateau. For children under 10 years, it is 3 seconds.

The maximum pause between reaching full inspiration and beginning the expiratory effort should not exceed 1 to 2 seconds; otherwise the FVC can be falsely reduced.

Acceptable versus Usable Tests

Acceptable Tests must meet the following 8 Criteria:

  1. Good Start (no back extrapolation error).
  2. No cough during the first second.
  3. No early termination.
  4. No valsalva maneuver.
  5. No leak.
  6. No obstruction of mouthpiece.
  7. No extra breaths.
  8. Achieves a one second plateau after a 6 second or greater blow.

An acceptable test meets all 8 criteria listed. This is to be considered the gold standard .

Useable trials are those that only meet criteria 1 and 2. When this occurs, repeat testing up to 8 trials in an effort to obtain 3 Acceptable trials. If only Usable tests are obtained, report results based on the 3 best Usable trials with observed limitations.


An ideal test session requires that 3 Acceptable tests be recorded with the two largest FVC and FEV1 Values reproducing within 150 ml. (Note, the old criteria was 200ml.

Slow Vital Capacity Reproducibility:

When using the Slow Vital Capacity maneuver, the subject must wear a nose clip. Conduct a maximum of 4 trials with a 1 minute rest between trials. The 2 largest VC values should reproduce within + 150 ml.