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Enough already with the natriuretic peptides


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I know it’s not necessarily what you read the Copperfield column for, but what I want to talk about today is B type natriuretic peptide (BNP).

Yes, that sounds a bit clinical, whereas you were actually anticipating an old fart sounding off on about how things were much better back in the day when we used to do loads of home visits, were up all night on call and took tonsils out on the kitchen table in our lunch hour. And yes, they were and we did.

But look, I’ve got a view on the BNP blood test and because I’ve got a view on it, it passes the blog test (if you’re still not sure, look towards the top of the page and you’ll see that ‘Blogs’ come under ‘Views’, OK?).

So, my view on the BNP is this: we are in the middle of an epidemic of BNP testing, that’s a really bad thing and it’s all our fault.

The vast majority with swolen ankles don't have cardiac failure, but one of a zillion other causes

I’ll keep this brief, but it goes like this. It seems to me that a patient cannot have swollen ankles nowadays without someone checking their BNP. Since when was that a thing?

BNP’s a good rule-out test for cardiac failure but the vast majority of patients with swollen ankles don’t have cardiac failure, they have one of a zillion other causes. And if they haven’t got breathlessness or a raised JVP then I’d argue that it’s even more stupid to do a BNP. This isn’t evidence based (I’ve checked and there isn’t any), it’s opinion based, which I prefer, anyway.

The consequences of all this indiscriminate testing are:

1. Increased lab test costs.

2. Huge numbers of false positives (the population with swollen ankles being those most likely to turn up such a result), causing anxiety.

3. Loads of unnecessary referrals for echocardiography or cardiology.

4. Because you have written ‘BNP’ on the biochem form, patients being offended that you are testing them for membership of a far-right fascist political party (admittedly, not such a problem where I work). And if you think that patients can’t be that sensitive, may I remind you that but I once had a patient upset that I had put her on Adalat Retard?

So will you people just stop with the inappropriate BNPs?

I must say, it was much better years ago when we were called out in the middle of the night for acute breathlessness, listened for basal creps, diagnosed acute LVF clinically and gave them IV furosemide, knowing that, next morning, they would be incredibly grateful, in acute urinary retention, or dead. Happy days.

Dr Tony Copperfield is a jobbing GP in Essex

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Readers' comments (7)

  • I had a patient offended that the recommendation note form from the consultant, had a box headed 'recommended treatment (therapeutic group if possible):' in which the consultants could write frusemide if they wanted, but she objected that the form assumed she needed psychological treatment for being mad.

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  • Frusemide, old boy :-)

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  • In Northern Ireland; I had an 88 yo female patient who launched a full packet of tablets back at me when I was doing a house call, this ricocheted off my head and into her fireplace,
    My offence was giving a very staunch protestant lady a packet of tablets that were coloured green, white and orange, the whole street she heard her blaring loudly that I could take my fffing fenian tablets back!

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  • My sympathies Anonymous Doctor-did you immediately refer her to Euthanasia Outpatients ? If only....

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  • David Banner

    Sadly mass BNP testing is the inevitable consequence of defensive medicine. When those swollen ankles eventually mutatate into SOB, raised JVP and orthopnea, some smart-ass in A&E will chirp how “your GP could have diagnosed this months ago with a simple blood test rather than just give you water tablets and a foot stool”. Bingo, complaint letter......

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  • AlanAlmond

    Ankle swelling? I just tell them all to stick their legs in the air like they just don’t care.

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  • A common scenario - a demented woman sits in her chair all day. The careers visit, are 'not happy' about her swollen ankles, phone for a doctor's visit then bugger off.
    2 hours later a doctor visits, patient has completely forgotten the careers even being there. Dr leaves a note for careers explaining the side effects of amlodipine.
    The whole thing is repeated when the careers are changed.

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