Making Sense of Testing

Behind the hype about health testing.
This guide looks at why scans and tests for well people aren’t always a good idea.

Published: 11 March 2008
All our guides are date stamped and reflect the scientific findings and knowledge available at the time of publication.

Did you Know?

A test result is not taken as a number in isolation. It gets compared to a range of values considered ‘normal’ for a healthy individual. This is called the reference range, and it’s what a doctor can use to interpret a set of results for individual patients.


We have released an update to this guide, focusing on Covid-19 testing. Download “Making Sense of Covid-19 Testing” here.


Adverts and media reports say that people with no symptoms, nor reason to suspect they have a disease can find out what they will get in the future, “reverse the disease processes before symptoms appear”, or even discover how they will die. People are promised instant results, valuable insights and ‘peace of mind’. What many people are getting is a lot of confusion and anxiety, ongoing trips to the doctor and, sometimes, unnecessary medical procedures. The guide presents a few insights and highlights common misconceptions about having health tests and scans.


This guide was produced in collaboration with The Royal College of Pathologists, The Association for Clinical Biochemistry and the Foundation for Genomics & Population Health.

What is the problem this guide is addressing?

Despite the huge deployment of established laboratory tests, and the unprecedented explosion in new technologies and marketing of testing to healthy people, there is still no system (equivalent to the British National Formulary for drugs) to provide doctors or patients with evidence on performance and usefulness of testing.

In this guide, GPs and scientists warn the public:

• most tests weren’t designed for well people,
• many tests are not researched or adequately regulated,
• tests are only one part of diagnosis,
• testing can cause harm, especially in well people.


Making Sense of Testing launched in Parliament with doctors and scientists speaking about the need for proper evaluation of diagnostic tests in order to improve services in the NHS, and to help the public and doctors to determine the value and safety of private testing and over-the-counter products in the face of heavy promotion. The guide had great reception in newspapers; with features in the Times, the Guardian and the Telegraph as well as segments on BBC Breakfast and BBC Radio 4’s Today programme. Tonight with Trevor MacDonald followed up with an investigative piece on ITV. Lifestyle magazines were very interested in the guide with write-ups in Harper’s Bazaar and Easy Living.

Published: 2 February 2017