Whenever a client of our office is alleged to be driving while under the influence, we are keen to verify if the breath or blood test is accurate. If the blood alcohol content is calculated by a breath test, for example, it is fundamental that the breath test machine is properly calibrated.

The legislature of the State of California recognized the importance of this by passing section 1221.4 (a)(2)(B) of Title 17 in the California Code of Regulations. Section 1221.4 requires that the instrument used to measure the breath alcohol content of a suspect undergo “periodic analysis of a reference sample of known alcohol concentration” to ensure the machine is properly calibrated. In the case of the Alcotest 7410, the calibration must be every ten days, or every 150 subjects tested, whichever comes sooner.