How is quality graded in diffusing capacity of lung for carbon monoxide (DLCO) testing?

Updated: May 14, 2020
  • Author: Kevin McCarthy, RPFT; Chief Editor: Nader Kamangar, MD, FACP, FCCP, FCCM  more...
  • Print
Answer

Answer

Quality grading for DLCO measurements is as follows:

  • Score of A: (1) VI/VC 90% or VI/VC greater than 85% and VA within 0.2 L or 5% of largest VA from another acceptable maneuver; (2) breath hold time of 8-12 seconds; and (3) sample collection less than 4 seconds
  • Score of B: (1) VI/VC greater than 85%; (2) breath hold time of 8-12 seconds; and (3) sample collection less than 4 seconds
  • Score of C: (1) VI/VC greater than 80%; (2) breath hold time of 8-12 seconds; and (3) sample collection less than 5 seconds
  • Score of D: (1) VI/VC greater than 80%; (2) breath hold time of less than 8 seconds or greater than 12 seconds; and (3) sample collection less than 5 seconds
  • Score of F: (1) VI/VC less than 80%; (2) breath hold time of less than 8 seconds or greater than 12 seconds; and (3) sample collection greater than 5 seconds

Only grade A maneuvers meet all acceptability criteria. The average DLCO values from two or more grade A maneuvers that meet repeatability criterion should be reported. If only one grade A maneuver is obtained, the DLCO value from that maneuver should be reported. If no grade A maneuver is obtained, maneuvers of grades B to D might still have clinical utility, and the average of such maneuvers should be reported. However, these deviations from the acceptability criteria must be noted to caution the interpreter of the test. Maneuvers of grade F are not useable.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!