Search
  • Stephen Biss

Measurement Uncertainty


A blood alcohol concentration result of 127 mg /100 mls (or any other 2 digit or 3 digit number) on an approved instrument does not mean that the subject's true blood alcohol concentration is exactly 127 mg / 100 mls. Any numerical result is subject to uncertainty that combines the possibility of error from calibration checks (plus or minus 10 mg/ 100 mls margin for acceptable cal checks and plus or minus .2C for acceptable simulator temperature variation) plus machine analytical error plus sampling error (different lengths of blow, where the breath came from in the body) plus individual body differences (breath temperature and blood breath ratio).


4 views0 comments