To think this nurse was unprofessional?

If I understand you correctly, @ThisCoolOP, the nurse checked one of your BP machines against the surgery’s one, and found yours was giving the same result as hers. So you can be sure that that one is measuring accurately, which is what you needed to know. Given that, her advice to throw the other one away seems logical to me.

Indeed. I was invited to take our machine into the surgery so it could be compared to theirs.

and I amongst other qualifications was a cardiothoracic and ITU nurse and a diastolic pressure of 100 is a cause for concern so the OP did exactly the right thing in seeing the practice nurse
most decent GP practices offer to calibrate your home machine against the machine at their practice for consistency in readings. They should also ensure that tyou are taking the BP correctly, fitting the cuff properly, sitting in the correct position.
The cheap BP machines that you buy for home use do start to fail after a while. I would throw both away and buy a new one.

Do you have any idea how busy nurses are and what theY now have to do to earn shit money? Do you go into a shop at random and ask them to check random machines as well? Get hold of the manufacturer

Thanks. I do know this. It seems @ThisCoolOP Is not so sure with all of the inverted commas. I am wondering why she is questioning the nurses practice.

But the sister getting the nurse to check her machine is, rather than just getting her bp checked. For the sister to check several times herself at different times
Why take in the machine and get the nurse to check it. The nurse does the bp, the one with the closest reading is kept, the other is binned.

Clearly the sister (and op) are worried about bp. Fine understand but why get a professional in a service already stretched to concentrate on her machine....why not by a third machine, see a pharmacist, borrow her sisters?

Actually this is a good suggestion

Last time when I was at my surgery the nurse said to me to bring my own blood pressure monitor to check if it gives accurate readings, and compare with the one at the surgery.

so Op did the right thing.

So the real issue is you don't really trust her enough to believe she gave you the right result.

My advice then would be to do the monitoring using the machine she did test. Then when your sister comes to her GP appointment to discuss the results, bring your machine in again and do the check again against the surgery one on the day. That should put an end to the wondering.

Well it sounds like most of you replying know fuck all about this issue and love being snidy and judgemental about how other people use the Doctor. If the NHS was funded properly you wouldn't be so petty and awful to people who need to use it for a valid service. If you saw the NHS website you would be surprised what they recommend you book an appointment for. Doctors aren't just sitting around waiting for you and your special important condition you know. They do see other people sometimes.
OP, just do as she says and use the machine she told you to. You are over thinking this.

Yes, I’m not saying you are lying! But to hear that account you would spend a chunk of time thinking wtf? It’s definitely one to get your head around.
Im wondering if the cuffs are different sizes or shapes? Or if your sister has big arms or very small arms?
I don’t think she would have lied about checking it either, it’s not worth her PIN.

I was put on bp medication for a short while and had to take some readings at home then go back. The nurse specifically asked me to bring my machine with me to my appointment so that she could compare readings and make sure my own one was accurate. I believe the machines should be calibrated every so often? I think it's quite reasonable to get a check up of your bp and ask her to check your machine at the same time.

Maybe you could learn how to take a manual reading? It's not that difficult. Your sister could too. That way you know you're getting the right reading every time

As she actually told you to bin one - which is quite an extreme thing to say - it's likely that she could judge just by looking at them which one was going to be the more accurate one.

Or she guessed - it was 50/50 chance.

I'm sure if the reading for the one she tested had been wildly off then she'd have taken a look at the second machine.

But it only does that on your sister, not on you or the other people you tested, ergo the problem is your sister not the machine.

Why Do you not think it important to have an accurate BP reading, given the consequences of it remaining high ? Do you not think the nurse thought it significant and that’s why the appointment was given ?

I don’t think it was that bad. I think you are a bit sensitive.
It sounds like a bit of a crazy story that only your SIL gets different readings, and the nurse did check one against her own, and said it was correct.
blood pressures are so variable from one minute to the next almost, I think a 10-15mmhg difference on a home monitor would not be too bad. Not ideal, but you would get a picture, and over time your sister would get her BP checked regularly.
the difference between 150 and 165 doesn’t make a big difference in treatment I think. They would both be cause for concern.
And if they were lower, say comparing 135 and 150 over a period of 7 days it would show a pattern of going higher or lower depending on the stress of the day etc.

I also think that the nurse might have just seen someone truly suffering with a terminal illness etc, and this might have been the best she could do in a jam packed schedule, you don’t always get to decompress between one person and the next.

I think you are kind to worry about your sister so much, she is very lucky.

So at this point why aren't you happy with the evidence from the test in the surgery that the one she tested is the right one to keep using, and either bin the one which offers the lower reading or just don't use it for your sister as she is the only one with a problem with it.