Table 6: Classification of quality control.

Quality

VIN/FVC (%)

TA

Sample

collection

time*

(seconds)

A

≥ 90

8-12 s

≤ 4

B

≥ 85

8-12 s

≤ 4

C

≥ 80

8-12 s

≤ 5

D

≤ 80

< 8 o > 12 s

≤ 5

F

≤ 80

< 8 o > 12 s

> 5

Quality A: meets all acceptability criteria. Report the average DLCOsb of two repeatable quality A maneuvers.

Unsuccessful repetition

(if two repeatable quality A maneuvers are not obtained):

1. Two or more maneuvers A not repeatable, but acceptable: Report the average DLCOsb of those acceptable maneuvers

2. Only one maneuver A is obtained: Report the DLCOsb value of that maneuver

3. Maneuvers A are not obtained: report the average DLCOsb of the maneuvers with grades B, C or D

4. Only F maneuvers are obtained: Do not report any DLCOsb value

Note: In each of these situations, these deviations from the acceptability criteria should be noted to alert the interpreter of the test results.

DLCOsb = single-breath pulmonary diffusion of carbon monoxide.

FVC = forced vital capacity.

TA = apnea time.

VA = alveolar volume.

VIN = inspired volume.

* Only in classic analyzers, in fast response analyzers it is necessary to reach the residual volume with a maximum of 12 seconds.

VIN/FVC ≥ 85% and alveolar volume within 200 mL or 5% (whichever is greater) of the largest VA of another acceptable maneuver.