Very much learnt rather than realised, but I didn't know why British medics use bm to refer to blood sugar measurement. The B has nothing to do with blood, but refers to the fact that the strips used to measure the level used to be manufactured by Boehringer Mannheim, a company since taken over by Roche. There appears to be a campaign to use bg (blood glucose) instead, but nobody's listening. I have been told that in Australia bsl (blood sugar level) is used; @Cinefactus can probably confirm or deny this. Everyone else has probably fallen asleep.