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Patients need better information on usefulness of blood tests finds new audit of UK primary care tests

Blood test tubes in a laboratory

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Primary Care Academic Collaborative (PACT) logo

Press release issued: 21 July 2023

An audit of blood tests in UK GP practices has found that 6.2% of test results led to a new diagnosis or confirmation of a diagnosis, and abnormal or borderline results were common with only around a quarter (26.6%) of patients having results in the normal range.

Authors of the University of Bristol-led study, published in the British Journal of General Practice, say that while these findings may be unsurprising to clinicians, they may be concerning or confusing to patients, especially when accessing results online.

The audit, which collected anonymised data on blood tests for over 2,500 patients from 57 GP practices in England, Scotland, Wales and Northern Ireland, also found that a quarter of tests may have been partially or fully unnecessary when reviewed retrospectively by another clinician.

Around half of tests (48%) did not lead to any change in management or reassurance, 13.4% led to further blood tests or repeat blood tests, and 2.7% led to further radiology tests.

The most common reasons for testing were symptoms (43.2%), monitoring of existing disease (30.1%), and monitoring of existing medications (10%).

Only around half of tests were requested by GPs, reflecting the multidisciplinary nature of primary care. On average 4.5 tests were requested simultaneously per patient.

The study, Why Test?, is the first from a new national collaborative of academics and primary care clinicians (PACT) and was supported by the National Institute for Health and Care Research Applied Research Collaboration West (NIHR ARC West) and NHS Bristol, North Somerset and South Gloucestershire Integrated Care Board Research Capability Funding.

Dr Jessica Watson, a GP and NIHR Clinical Lecturer in General Practice at the Centre for Academic Primary Care, University of Bristol, said: “Rates of blood testing in primary care have increased over the last twenty years. In this study, we wanted to explore who requests blood tests and why, and what the outcomes are.

“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. 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.

“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.

“We are grateful to PACT members for collaborating on this research. Without their help, this data collection would not have been possible.”

The findings were presented this week at the Society for Academic Primary Care Annual Scientific Meeting in Brighton.

Paper: Why test? Study: a UK-wide audit using the Primary Care Academic CollaboraTive to explore the reasons for primary care testing. Published in British Journal of General Practice. July 2023. (Author accepted manuscript)

For further information about PACT, visit

Watch the Why Test? Study animation.

Further information


Over 100 million blood tests are ordered by GPs in England every year. (Source: NHS England)

About the Primary care Academic CollaboraTive (PACT)

PACT is a collaborative research network of enthusiastic Primary Care team members who want to participate in high impact projects and learn more about research. Established in 2019, PACT now has over 600 members across the United Kingdom and is continuing to grow. PACT members include medical students, junior doctors, GP trainees, GPs, nurses, physiotherapists, physician associates, pharmacists and paramedics working in Primary Care. PACT empowers its members to gain first-hand experience in large multi-centre PACT research projects and supports them through the data collection process. All primary care clinicians and researchers are welcome to join PACT via our website
Follow us on Twitter: @GPPACT

About the Centre for Academic Primary Care

The Centre for Academic Primary Care (CAPC) at the University of Bristol is a leading centre for primary care research in the UK, one of nine forming the NIHR School for Primary Care Research. It sits within Bristol Medical School, an internationally recognised centre of excellence for population health research and teaching.
Follow on Twitter: @capcbristol

About the National Institute for Health and Care Research (NIHR)

The mission of the National Institute for Health and Care Research (NIHR) is to improve the health and wealth of the nation through research. We do this by:

  • Funding high quality, timely research that benefits the NHS, public health and social care;
  • Investing in world-class expertise, facilities and a skilled delivery workforce to translate discoveries into improved treatments and services;
  • Partnering with patients, service users, carers and communities, improving the relevance, quality and impact of our research;
  • Attracting, training and supporting the best researchers to tackle complex health and social care challenges;
  • Collaborating with other public funders, charities and industry to help shape a cohesive and globally competitive research system;
  • Funding applied global health research and training to meet the needs of the poorest people in low and middle income countries.

NIHR is funded by the Department of Health and Social Care. Its work in low and middle income countries is principally funded through UK Aid from the UK government.

The NIHR is the research partner of the NHS, public health and social care.

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