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‘Diagnostic downshift’: clinical and system consequences of extrapolating secondary care testing tactics to primary care
  1. Imran Mohammed Sajid1,2,
  2. Kathleen Frost3,
  3. Ash K Paul4
  1. 1 NHS West London Clinical Commissioning Group, London, UK
  2. 2 University of Global Health Equity, Kigali, Rwanda
  3. 3 NHS Central London Clinical Commissioning Group, London, UK
  4. 4 NHS South West London Health and Care Partnership STP, London, UK
  1. Correspondence to Dr Imran Mohammed Sajid, NHS West London Clinical Commissioning Group, London, London, UK; imransajid{at}


Numerous drivers push specialist diagnostic approaches down to primary care (‘diagnostic downshift’), intuitively welcomed by clinicians and patients. However, primary care’s different population and processes result in under-recognised, unintended consequences. Testing performs poorer in primary care, with indication creep due to earlier, more undifferentiated presentation and reduced accuracy due to spectrum bias and the ‘false-positive paradox’. In low-prevalence settings, tests without near-100% specificity have their useful yield eclipsed by greater incidental or false-positive findings. Ensuing cascades and multiplier effects can generate clinician workload, patient anxiety, further low-value tests, referrals, treatments and a potentially nocebic population ‘disease’ burden of unclear benefit. Increased diagnostics earlier in pathways can burden patients and stretch general practice (GP) workloads, inducing downstream service utilisation and unintended ‘market failure’ effects. Evidence is tenuous for reducing secondary care referrals, providing patient reassurance or meaningfully improving clinical outcomes. Subsequently, inflated investment in per capita testing, at a lower level in a healthcare system, may deliver diminishing or even negative economic returns. Test cost poorly represents ‘value’, neglecting under-recognised downstream consequences, which must be balanced against therapeutic yield. With lower positive predictive values, more tests are required per true diagnosis and cost-effectiveness is rarely robust. With fixed secondary care capacity, novel primary care testing is an added cost pressure, rarely reducing hospital activity. GP testing strategies require real-world evaluation, in primary care populations, of all downstream consequences. Test formularies should be scrutinised in view of the setting of care, with interventions to focus rational testing towards those with higher pretest probabilities, while improving interpretation and communication of results.

  • primary healthcare
  • general practice
  • radiology
  • pathology
  • diagnosis

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  • Contributors Authorship includes expertise in primary care, public health commissioning, diagnostic pathway development and contract management. IMS and KF have led on NHS sector-wide diagnostic optimisation, procurement and quality improvement work for the past 4 years, which underpinned the learning for this article. Stakeholder engagement has included commissioners, GPs, specialists, laboratory and radiology staff, as well as patient representatives via several forums, echoing commonly under-recognised recurrent themes. IMS, general practitioner, adjunct lecturer in health policy and clinical commissioner, drafted the manuscript, which was reviewed and edited by coauthors KF and AKP. KF is a commissioning programme lead, previously a physiotherapist and pathology manager. AKP is a consultant in public health also working in commissioning of services, as well as the NHS national evidence-based interventions programme, who provided further evidence review for the article. IMS is responsible for the overall content and is the primary correspondent.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.