ABA Sequences v ACA Sequences
Updated: Apr 9, 2022
To explain to the Court, the differences between ABA (Esc Esc B) and ACA (Esc Esc C) sequences
To confirm that ABA sequences are not recorded in COBRA data but ACA sequences are recorded in COBRA data.
To explain to the Court why the calibration checks at 40 or 50, 100, and 300 during annual inspections do not appear in COBRA data disclosed.
Sample cross-examination of Crown expert to clarify ABA (and ACABA) sequences v. ACA sequences for the Court:
Q. Just, before we go any further, there are two different kinds of sequences that can be used for using a wet bath simulator. One is the A-B-A sequence, one is the AC- A sequence. Could you explain for everybody’s benefit what the difference is between the two – those two kinds of sequences? A. So, the first is where you’re providing a sample of breath. So, you are using a simulator and you’re blowing through it, as if a person was providing a sample. And then it’s reading the concentration of alcohol in the sample chamber. And the – an – sorry, that’s an A-C-A. No, sorry, that’s an A-B-A, where you are the pump and you are providing the sample into the instrument. An A-C-A is where you’re using a calibration check. It’s a stand-alone
calibration check. So, you’re using a solution that’s placed in a simulator, and you’re recirculating that, and that’s what’s reading.
[The following is important to understanding what is saved (in Ontario) in COBRA data. You will need to understand these differences if you are bringing an O'Connor application for COBRA data. If an ABA sequence is not recorded in COBRA data there is no point in asking for it. ACABA subject test sequences and ACA sequences are saved in (Ontario) COBRA. ABA sequences are not saved in (Ontario) COBRA.]
Q. And just also, for everybody else’s benefit, A-B-A results are recorded – are not recorded in Cobra Data. A-C-A are recorded in Cobra Data. A. That's correct. But of course then, I don’t know what also happened with respect to how many – did he allow the solution to warm up properly, which could also explain the low results at the 100 and the 50 or the 40. I mean, those are possible other explanations for why those are reading low.