Definitions of Terms

A Standard - Also called an Ethanol Standard or Gas Standard.  A solution of ethanol in water (wet standard) or mixture of pressurized gas, usually ethanol in nitrogen (dry standard) certified to produce a sample containing a predictable alcohol concentration.

Expected Value/Target Value - The result expected to be reported from the standard at the time of the accuracy check or calibration.

Quality Assurance Plan (QAP) - A set of criteria established by the manufacturer of the instrument and/or a testing program manager that establishes parameters for conducting accuracy checks and calibrations under a given testing program.

Calibration Log - A record of accuracy checks and calibrations performed on a specific breath alcohol testing instrument.

Accuracy Check - Also called a "Calibration Check" or "External Calibration Check". Checking an instrument for accuracy against a known standard.  This process is much the same as running a sample on a subject, but in this case the operator knows what result the instrument should produce. It only checks to see that given a known gas value registers correctly within tolerances defined by your testing protocol.

Calibration - Setting (adjusting) an instrument's sensitivity to properly report the known value of a standard.  The procedure is only done when your instrument's Accuracy Check result falls outside of the acceptable tolerance level stated in your QAP.  All calibrations should be followed by an Accuracy Check to ensure that the adjustment is correct.