Which of the Following Are Necessary to Ensure a Valid

Multiple Choice

Which of the following are necessary to ensure a valid single-breath diffusing capacity of the lungs (DLCO) test result?
1) Two or more acceptable tests should be averaged.
2) Breath-hold time should be between 3 and 5 sec.
3) Corrections for hemoglobin (Hb) and COHb should be included.
4) The maneuvers should be reproducible to within 10%.

A) 1, 2, and 3 only
B) 2 and 4 only
C) 1, 3, and 4 only
D) 1, 2, 3, and 4