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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