CareFusion Smoke Check Manuel D'utilisation page 18

Ask the subject to inspire and hold their breath.
The unit will auto-zero for twelve seconds during which time the
following will be displayed:
Important note: the unit must not be used during this period.
After twelve seconds the display will change to:
The subject may now seal their lips around the mouthpiece and exhale
slowly and fully if they cannot hold their breath any longer. However,
more accurate results will be obtained if they hold their breath until
the buzzer sounds and the display changes to:
Bat
7-10 ppm
Wait
Blow
0-6 ppm
Gas
Wait
Wait
0-6 ppm
20+ ppm
11-20 ppm
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