DP's blood systolic pressure hovers around 135-140mmHg. I'm an academic in health field and I know that this is bordering on or close to high, and have let him know this in context of potential lifestyle changes (social smoker, drinker, big meat eater etc.) or at least just something to be aware of. He's late 30s so worth knowing, right?
He was visiting his DM in hospital recently and member of staff was taking her BP and he asked staff member what the threshold is because I've told him 140.
She told him her chart says 180. He laughed and said 'oh I'll tell gf that!' (I wasn't there, this is what he told me). I think he was pleased as he doesn't want to give up bacon sandwiches 
Now, I don't know if that was a bespoke threshold for that patient or something, it must be, but I do know that for a normal adult, consistent BP of 140+ is classed as high and needs looking at.
When he told me this story, I said that might be the threshold set for your DM but for you, it's wrong. He just said 'OK' in a patronising 'let's agree to disagree as the nurse must be right' tone.
Aibu to be a bit miffed about this? Suppose I'm being a bit precious but it's not the first time my knowledge has been questioned by him.
I told him and his DSs that it was light saber not saver and they didn't believe me. Asked a 4 yo boy later and only when he confirmed did they believe me. Similar story with Bond - MI5 or 6? Had to google to prove I was right in the end (6, if you're wondering 
).
Do I have a real issue with needing to be right, or am I right (ha!) in feeling a bit annoyed at these sorts of things if they keep happening?
For the record, I'm not an argumentative person (used to be but have mellowed with age/DCs) I'm open minded and more than happy to have discussions and figure out the facts, but why does he keep questioning me and assuming I'm wrong to the point that I feel the need to prove I'm right?
The fact that this happened in front of his DM is also annoying. They often ask me for help deciphering medical info, and I feel this undermines me a bit.
I know, I know, IABU. But grrrrrr 