Login / Register
Change Your Country

Alco-Sensor VXL Accuracy Check Procedure

Accuracy checks should be performed periodically to validate accuracy and to establish a performance record for your ASVXL instrument.  The frequency should be determined by your Quality Assurance Program.

Please note that the display screens for performing accuracy checks on the Alco-Sensor VXL may vary by software version.  The test sequence described here may be slightly different than the sequence on your ASVXL device.  We will be demonstrating the procedure on the General Screener version of the ASVXL.

Prior to running an Accuracy Check you should make certain that the Standard you will be using is current and all of the operating parameters for that device have been met:

  • Have as little tubing as possible between the gas out port of the standard and the mouthpiece of the Alco-Sensor VXL.
  • Check Expiration Date (on Wet Bath Simulator Solution or Dry Gas Tank)
  • Check temperature of the Wet Bath Simulator (if used)
  • If using a Dry Gas standard, ensure the tank is at room temperature
  • Purge the simulator tubing or dry gas regulator for several seconds
  • Know the current expected value of the Standard
  • If you keep a calibration log, it should be present

Ensure the tools listed below are present:

  • Dry Gas Standard
  • Regulator with a 6 Liter Per Minute regulator and mouthpiece adapter
  • True-Cal or True Cal II Device (if used)
  • Alco-Sensor VXL
  • New Mouthpiece

Note: A calibration standard can be a:

    • Dry Gas Cylinder and Regulator
    • Wet Bath Simulator and Solution

For this demonstration, a dry gas tank is used as the standard – value (at sea level) of .082%. a True-Cal Device was used to give the expected value of the standard at the time of our demonstration – the True-Cal will show the expected gas value adjusted for the current atmospheric pressure. Therefore, the target value for this demonstration is .080.

Alco-Sensor VXL Accuracy Check Procedure Part 1
  • Turn on the ASVXL and check the temperature in the top bar.  Temperature for an accuracy check must be between 10 – 32 degrees Celsius.
  • Then press the button below the Test Menu command on the display (bottom right scroll button).
  • Use the right scroll button to scroll down in the menu until “MAIN MENU” is highlighted.
  • Press the yellow trigger button to select “MAIN MENU”.
  • Enter your password when prompted.  (Check with your supervisor if you have not been given a password.)
  • Choose the highlighted option: “QUALITY ASSURANCE”.  Then select “ACCURACY CHECK” from the list using the trigger button.
  • Enter the Standard Type you are using.
    • Dry
    • Wet

Scroll to Main Menu
Enter your Password 
Choose Quality Assurance from the Main Menu
  • The ASVXL will display the Standard Value.  This is the sea level value of the standard being used and can be found on the label of the bottle.  If the standard value you are using is different, you must change the number here.
  • The ASVXL will display the Target Value.
  • If your ASVXL has an on-board barometer, this number is calculated automatically and displayed later in the sequence.
  • Press the button on your True-Cal device or look at the chart on the Dry Gas tank label to get the Target (or Expected) Value of the standard.
  • Then enter the Target Value

NOTE:  Wet Bath Simulator users will not be asked about the Target Value since the Standard and Target values for a wet standard are the same.

Target value of standard
  •  Next, you will be prompted to enter or verify identifying information about your gas standard.
    • Lot Number
    • Tank Number
    • Tank Expiration Date


Alco-Sensor VXL Accuracy Check Procedure Part 2
  • The ASVXL will briefly display the Test Number and then the Target Value.
  • Observe the air blank to insure no alcohol is present in the sampling system prior to the procedure.
  • Mount a clean, unused mouthpiece when prompted by the ASVXL display.
  • Purge the regulator for 1-2 seconds.
  • When the ASVXL display shows “Submit Sample”, connect the mouthpiece to the regulator hose and press the regulator button to introduce the gas through the mouthpiece.
  • The regulator button will be depressed for a total of 7-8 seconds, but you will depress the yellow Trigger button to capture a sample on the 5th or 6th second.
  • If you are using a 6 Liter Per Minute (LPM) regulator, you will see the red lights on the side of the device flashing and the ASVXL can auto sample the gas.

Connect mouthpiece to regulator hose
As gas is flowing through the 6LPM regulator, the red lights will illuminate
    • The ASVXL display will show “Analyzing Sample” indicating it is calculating the result of the accuracy check.
    • The result of the accuracy check will be displayed in 3 digits.  If the result is at or within the tolerance of accuracy then the instrument is considered to be in calibration.  The tolerance range for the standard ASVXL is set to +/- .005 % BrAC.

    • NOTE:  if the result is outside of the tolerance, then subject tests will be disabled and a Status Message will be displayed.   This situation will require a Calibration Adjustment followed by a successful accuracy check to repair the ASVXL device.


If your device is set up to communicate to a printer, then you will be prompted to place the ASVXL into the Docking Cradle for printing.  If you are not set up for printing, then the accuracy check sequence will end at this point.

Accuracy Check – Alco-Sensor VXL Record Keeping
To demonstrate compliance with your program’s QAP (Quality Assurance Plan) it is best to keep a record or a Calibration Log for each device used for testing.  The log should contain the results of all accuracy checks and calibrations for each instrument.  This log may become a crucial piece of evidence should your test results be challenged.  The log may include information such as:

  • Date
  • Time
  • Procedure performed (Accuracy Check or Calibration)
  • Name of Technician performing procedure
  • Location
  • Identification of the Standard including Lot Number of the Standard
  • Expected Value of the Standard
  • Result of the Accuracy Check or Calibration

For more information about procedures for your Intoximeters instrument, please refer to your

  • Operator’s Manual
  • or email Intoximeters for Technical Support
  • or phone the Technical Support Department at 314.429.4000

For additional maintenance information please click here.


Your Cart