Abstract: Poster Presentations |

Absolute, Rather Than Percent Differences, can be Used to Assess Measurement Variability for DLCO FREE TO VIEW

Robert O. Crapo, MD*; Neil R. MacIntyre, MD; Robert L. Jensen, PhD
Author and Funding Information

LDS Hospital/University of Utah, Salt Lake City, UT


Chest. 2004;126(4_MeetingAbstracts):797S. doi:10.1378/chest.126.4_MeetingAbstracts.797S-a
Text Size: A A A
Published online


PURPOSE:  Punjabi reported test reproducibility for DLCO was best assessed by absolute differences of 2.0 to 2.5 DLCO units between tests (Chest 2003; 123:1082-89). This recommendation has been criticized because it was based on only one instrument manufacturer and one laboratory.

METHODS:  Using a retrospective design to avoid influencing laboratory procedure, 16 laboratories from the ATS lab registry program submitted complete data for two DLCO trials (DLCO, VI, VA) and patient demographic data from 50 consecutive laboratory reports (792 records). Data were obtained from 22 instruments representing nine different models and four manufacturers. The figureillustrates percent and absolute differences between the two DLCO measurements by average DLCO.

RESULTS:  There is strong nonlinear relationship between percent difference and average DLCO and a trivial linear relationship between absolute difference and average DLCO. After excluding four outliers, absolute differences for 70% of the tests were < 1 DLCO unit, 91.3% were < 2.0 units and 95.5% were < 2.5 units. These data confirm the Punjabi’s findings in 16 laboratories using a wide variety of instruments.

CONCLUSION:  Acceptable DLCO variability should be assessed as absolute differences less than 2 or 2.5 DLCO units.

CLINICAL IMPLICATIONS:  Doing so simplifies DLCO testing and may reduce the number of tests required to meet acceptability criteria.

DISCLOSURE:  R.O. Crapo, None.

Wednesday, October 27, 2004

12:30 PM - 2:00 PM




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543