Alco-Sensor III Accuracy Check Procedure - Page 1

An Accuracy Check should be performed periodically. The frequency should be determined by your Quality Assurance Program.

Below are basic Accuracy Check instructions for the Intoximeters Alco-Sensor III breath testing instrument.

Tools Required: Before beginning have items available: instrument, calibration standard, new mouthpiece


  • Dry Gas Standard & Regulator
  • True-Cal or True-Cal II Device
  • Alco-Sensor III
  • New Mouthpiece



Note: A calibration standard can be a: 
  • Mini-Alco Can (for non-evidentiary testing applications only),
  • Dry Gas Cylinder and Regulator
  • Wet Bath Simulator and Solution



For this demonstration, a dry gas cylinder is used as the standard - value (at sea level) of.082%.

  • A True-Cal device was used to give the true value of the standard at the time of our demonstration
  • the True-Cal will display an adjusted, or expected, gas value for the current atmospheric pressure
  • Therefore, the target value for this demonstration is .081

True-Cal displays .081