Micro Direct MicroLab Operating Manual page 19

The calibration error for expiration
and inspiration at each flow rate
are displayed. The calibration
error should be less than 3.5%. If
a greater error is shown, repeat
the procedure ensuring that the
syringe is emptied and filled in a
smooth manner without jerking the
handle. If an error greater than
3.5% is still shown, inspect the
turbine transducer and clean if
necessary.
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