This site is intended for health professionals only

One in four blood tests in general practice may be unnecessary

One in four blood tests in general practice may be unnecessary

A quarter of blood tests done in general practice may be unnecessary, say primary care researchers who found half would not lead to any change in management.

An audit of blood tests for more than 2,500 patients at 57 GP practices in the UK also found abnormal or borderline results are common with only 26% of patients receiving results in the normal range.

The research led by the University of Bristol found just 6% of test results led to a new diagnosis or confirmation of diagnosis, they reported in the British Journal of General Practice.

Study lead Dr Jessica Watson, a GP and NIHR clinical lecturer in general practice said rates of blood testing had increased over the past two decades but no one had looked at who was ordering tests and why and what the outcomes were.

The Why Test? Study also presented at the Society of Academic Primary Care conference in Brighton has implications for helping patients have ‘realistic expectations’ of test results, she added.

It showed the commonest reasons for testing in primary care were investigation of symptoms (43%), monitoring of existing disease (30%), monitoring of existing medications (10% and follow up of previous abnormalities (7%).

Around 1.5% of tests looked at in the study were done simply because the patient requested it. Half were requested by GPs ‘reflecting the multidisciplinary nature of primary care’, the researchers said.

The analysis was done by 57 clinicians taking part in the Primary Care Academic CollaboraTive (PACT). They found that on review about a quarter of tests were partially or fully unnecessary.

They also found that 48.8% did not lead to change in management or reassurance and 13% led to further or repeat blood tests.

The ‘cascade effect’ of a test leading to more tests, imaging, appointments and referrals needs to be put in the context of an already overstretched health service, they noted.

While the findings are unlikely to surprise practicing clinicians, there are important implications ‘given the move to offer all patients in England with access to their blood test results via the NHS App’, Dr Watson said.

More work is needed to understand how patients will interpret borderline results – which happened with high frequency in the analysis, the research team added.

‘If patients see that their test results are outside the reference range it could potentially trigger alarm,’ they concluded.

‘The results have important implications for how primary care clinicians talk to patients about blood tests, to ensure that they have a better of understanding of why a test may or may not be necessary and realistic expectations of the role of blood tests in their care,’ said Dr Watson.

‘Many tests don’t lead to a diagnosis or change in treatment, although they may still be important to rule something out or provide reassurance.’

She added: ‘There is also a need for better evidence to inform judgements on whether a test is necessary or not, as sometimes this judgement is only possible with hindsight when test outcomes are known.

‘Unnecessary tests could lead to increased anxiety for patients, increased workload for GPs and increased costs for the NHS. We need better evidence to help us ensure that patients get the right test at the right time.’


Visit Pulse Reference for details on 140 symptoms, including easily searchable symptoms and categories, offering you a free platform to check symptoms and receive potential diagnoses during consultations.


Please note, only GPs are permitted to add comments to articles

John Graham Munro 3 August, 2023 5:45 pm

You’d not get this co-operation with X-Rays—–Ultrasounds—-E.E.G.s——you’d soon get short shrift from their dept.

ian owen 3 August, 2023 6:07 pm

25%? Is that all? And bear in mind 95% of vitamin D’ are…

Turn out The Lights 3 August, 2023 8:07 pm

But most are done to please lawyers not to alter management!

Slobber Dog 3 August, 2023 9:21 pm

Hindsight is a wonderful thing.

Dylan Summers 4 August, 2023 8:26 am

Not a surprise. But as ToTL implies, you face legal and regulatory jeopardy for failing to do a test, not for doing one.

David Jarvis 4 August, 2023 8:54 am

99 out of 100 statin prescriptions are potentially pointless but we do that to protect one. But you don’t know which one. I really hate smart arse retrospective studies like this. Especially with no consideration of the burden of risk. Easy to criticise those who take the risk. Just like smart arse CQC inspectors or Junior A&E Drs. Ignorance is truly bliss and experience shows that patients get seriously sick when you least expect from what you least expect and our regulators expect perfection with inadequate resources. Remove the resource because you no better and that is fine. I will just refer the risk at much greater expense and to the detriment of waiting lists.

David Banner 4 August, 2023 9:26 am

And once the punters all have full access to their records it will become far worse. When they see Emis Web’s terrifyingly ominous red exclamation mark next to a haematocrit 0.01 below the normal range (which some reckless incompetent GP filed away as “no action required”) an endless barrage of the Worried Well’s emails and calls will swamp an already overwhelmed system with demands for explanations, appointments and retests.

As stated above, the labs need to toughen up the testing criteria (as many are thankfully already doing over frivolous Vit D requests) so we can regretfully inform patients that whilst we would love to be able to check their serum rhubarb, those nasty horrible lab boffins won’t let us.

And if the GMC continue to keelhaul hapless GPs for “failure to diagnose/investigate”, don’t expect the deluge of pointless blood tests to reduce any time soon.

Rogue 1 4 August, 2023 9:56 am

And now you have a raft of Noctors ordering bloods on your behalf too, these numbers are only going to go up

John Glasspool 4 August, 2023 11:11 am

Annual TFTs for people on thyroxine replacement? Total waste of time but mandated by the DoH. I wish people who produce studies like this would give up and go back to full-time General Practice.

David Church 4 August, 2023 2:06 pm

There is a difference between “did not lead to a change in management” and “would not lead to a change in management”.
Although, where the management is “I am not sure if it is safe to continue this diuretic in case the potassium has gone too high”, a completely normal UEs would actually change that management to “i am reassured that it is currently safe to continue this diuretic because the potassium has NOT gone too high” Which could actually be considered a significant change??

David Church 4 August, 2023 2:08 pm

I was going to write that if we could rely on private test results being accurate and quality controlled (and actually in the same units as NHS ones with identical ‘normal ranges’), then perhaps a very much greater percentage of NHS blood tests could be considered unecessary : we could let patients choose – an maybe stop ‘prescribing’ and let them buy their own choice of drugs too? It would save a lot of NHS time. And that is only the ones still living.

Fay Wilson 4 August, 2023 5:56 pm

And bears s*** in the woods.
Now tell us something more worthwhile: which one in four is it?

Simon Gilbert 4 August, 2023 9:41 pm

“75% of blood tests were appropriate” is another way to look at it.

John Graham Munro 4 August, 2023 11:11 pm

Simon Gilbert
Apprpriate = i’ve got a hunch?

Carpe Vinum 7 August, 2023 9:38 am

Define “unnecessary” – as a mechanism for getting a hypochondriacal gasbag out of my room and rescuing my dwindling sanity, I would suggest a few harmless blood tests are massively beneficial!