NSC director Dr Anne Mackie exclusively revealed plans for the guidance in an interview with GP last October (GP, 16 October 2009).
The guidance warns of potential harm from endorsing screening that has insufficient evidence to show benefit. It has been produced in response to approaches made to GPs by private firms offering screening.
Private tests are available for a range of conditions, including abdominal aortic aneurysms, heart failure and carotid artery stenosis.
Launching the guidance, Dr Mackie said: 'Patients are increasingly turning to their GPs for advice, and we hope this guidance will enable practitioners to help their patients make the best choices.'
Dr Steve Laitner, a GP and consultant in public health medicine, said there had been an increase in patients being offered private screening.
'GPs provide valuable advice and support to patients in this area and I hope this new guidance will help them in supporting their patients,' he said.