But how accurate are these self testers?
Personally I wouldnt like to trust them.
Not as accurate as the ones the police use, and even then the police only use theirs as a guide as to if they arrest you pending further tests back at the nick on more accurate testing equipment or a blood test.
From what I gather, the results can vary by 15% depending on the individual, so i guess the self testers and ones the police use are based on this and allow for worse case scenario to be on the safe side. All very debatable and when you factor in how long it must take to get into your blood and out of, your body size and how much blood you have, then the only sure safe bet, if you value your license, is to not drink at all.
If you do wish to chance a drink, or value one for the road, more than your license, at least the self test kits give you some sort of guide as to where you stand. Personally I wouldn't trust them anymore than i trust myself when I've had drink ..