All tests can sometimes cause more harm than good

Inflammatory marker tests, such as C reactive protein, are simple, inexpensive, and commonly used in both primary and secondary care. 3 When we interviewed GPs about their use of inflammatory marker blood tests in primary care, all doctors mentioned potential harms as well as benefits of testing. 4 These could be divided into several categories; harms of the test itself, workload and financial costs, medicalisation of a patient's problem, patient anxiety, downstream costs, and harms of overdiagnosis. Overuse of diagnostic tests might reflect a societal culture of increasing risk aversion and rising medical litigation, as well as a culture in medicine that "evinces a deep rooted unwillingness to acknowledge and embrace uncertainty." Tolerating uncertainty- the next medical revolution? N Engl J Med 2016; 358: 1713- 5. doi:10.1056/NEJMp1606402. pmid:27806221.