Oh I agree. I think if you can get normal range LFTs recorded, or show improving LFTs from the recorded date of last drink, then it can help in case the CDT result comes up a little high for some reason.
I'd be interested to know from DVLA what their actual process is for satisfying themselves of the actual last drink date of an applicant based on last drink date in GP records, NHS or private LFTs, private CDTs, etc which all get sent in as evidence by some applicants.
Reading these forums it seems to me like DVLA don't have much consistency in their approach to this, especially for applicants who on their medical records have alcohol misuse, dependency, or mental health problems. I read one case on here of someone who had been sober for years, DVLA had given them their licence back a few years back, and then one 'tip off' from a disgruntled friend or family member and they had their licence revoked on medical grounds and had to start proving abstinence again and it took months to sort. Imagine you've been sober for years and you think you've got your life on the right track, but then learn that any random member of the public can get your licence taken away, which might mean losing your job or access to your children who live further away etc, basically for the rest of your life.
Yeah on my DDRS course they gave lots of tips about the medical and drinking. The provider was actually really good and said even after the course, if you need any advice etc just give them a call. But I think some providers are better than others at this.
Quite a few studies show it's more accurate, less intrusive (only requires a finger prick instead of a veinous blood draw), and goes back slightly further in time at around 28 days. I believe DVLA have signed a CDT testing contract though so not sure we'll move to PEth before that expires? Who knows though!