Single-breath diffusing capacity for carbon monoxide instrument accuracy across 3 health systems

Area of Science:

• Pulmonary Medicine
• Medical Device Performance
• Diagnostic Accuracy

Background:

• Diffusing capacity of the lung for carbon monoxide (DLCO) measurement is prone to significant variability.
• This variability can lead to critical clinical consequences.
• Assessing instrument performance is crucial for reliable DLCO testing.

Purpose of the Study:

• To evaluate the accuracy and performance of DLCO instruments in hospital laboratories.
• To identify sources of variability in DLCO measurements.
• To assess the utility of a DLCO simulator for instrument calibration.

Main Methods:

• Tested 23 DLCO instruments across three healthcare systems using a DLCO simulator.
• Evaluated accuracy based on the absolute difference from target DLCO values (< 2.0 mL/min/mm Hg).
• Assessed the accuracy of inspired volume measurement and gas sensors.

Main Results:

• 43% of tested DLCO instruments (10 of 23) were inaccurate.
• Mean absolute deviation from target DLCO was 1.80 mL/min/mm Hg.
• Inspired volume measurement errors affected 48% of devices; gas analyzers performed adequately.

Conclusions:

• A significant portion of DLCO instruments exhibit unacceptable accuracy.
• Instrument inaccuracy is mainly due to faulty inspired volume measurement, not gas analysis.
• Regular simulator testing can improve DLCO instrument performance and inter-laboratory consistency.