The figures are considerable: the NHS carries out more than two million pathology tests a day, which cost £3 billion a year, with primary care accounting for more than a third of the work.
GP's analysis of the figures finds that variation is common and startling: the costs of routine biochemical tests vary from 25p to £10.87, blood tests from 24p to £13.28, histology from £1.44 to £229.81 and immunology from 65p to £31.91.
Reasons vary but can include laboratories incurring higher costs as they offer more complex or specialist tests or simply not being large enough to gain economies of scale.
Speaking exclusively to GP, former health minister Lord Warner, who commissioned a 2008 review of pathology services that found the NHS could save £500m by reorganisation and modernisation, urged commissioners to 'bite the bullet'.
He added: 'It's an eternal truth that small is not beautiful, particularly in routine tests, as most common pathology tests are. The evidence from the rest of the world is that you have to scale up.'
GPs may in the past have felt that such costs were low on the list of things to scrutinise. But as more long-term illness is managed for an increasingly ageing population, demand for pathology services will inevitably increase.
With an increasing emphasis on quality, patients and GPs may also have higher expectations about what healthcare should deliver.
Could a test that historically takes 10 days be delivered in three, enabling the GP to deliver better care?
Inevitably there will be concerns that increased competition for tendering of pathology contracts could mean small, local hospitals losing out and open doors for independent providers.
Given the scale of the figures involved, it's an issue that merits at least consideration by GPs and their CCGs, particularly if the results are improved care for their populations.