Three cancer screening programmes have been paused across Scotland due to the coronavirus pandemic.
The Scottish government said no additional patients would be invited until further notice.
Screenings for breast, cervical and bowel cancers are affected as well as Abdominal Aortic Aneurysm (AAA) and diabetic retinopathy eye testing.
Results for those recently screened or who have returned home test kits will continue to be processed.
Pregnancy and newborn screening programmes, including tests offered during pregnancy and just after or near birth, will continue "where logistically practical".
The measure is designed to reallocate healthcare staff to support other essential services, including Covid-19 laboratory testing and covering for colleagues who are unwell or self-isolating.
Public Health Minister Joe FitzPatrick said: "This has been a difficult decision to take, but it is important to be aware that these screening programmes are focused on a well population, who are not known to have the conditions they are screened for.
"I want members of the public to be assured we will restart screening programmes as soon as it is safe to do so following clinical advice.
"When this happens invitations will be re-issued and appointments will be rearranged."
The estimated numbers affected per quarter each year, based on the most recent statistics are:
- 248,177 patients received bowel screening, 220 of whom were diagnosed with cancer.
- 46,596 patients received breast screening, of which 291 were diagnosed with cancer.
- 101,963 patients received cervical screening, of which 341 were diagnosed with invasive cancer.
The programmes affected include mammograms, smear tests and home test kits for bowel cancer.
AAA screening, which involves an ultrasound of the abdomen, and diabetic retinopathy, which requires images to be taken of the eye, have also been put on hold.
Chief medical officer Dr Catherine Calderwood acknowledged the risks to individuals through delayed diagnosis.
But she said they needed to be weighed against the pressures on the NHS posed by the virus
Dr Calderwood added: "The programmes will be potentially fragile due to staff absences and there are clear risks to patients in being asked to attend for screening.
"The redeployment of staff to work in other areas is also valuable as part of our national effort to tackle the effects of Covid-19."
Robert Music, chief executive of Jo's Cervical Cancer Trust, said the announcement was "not ideal" but accepted difficult decisions are having to be made across the NHS.
He added: "Cervical cancer remains a rarer and slow growing cancer, therefore we urge people finding appointments for screening or even treatment of cell changes postponed not to worry.
"While there will undoubtedly be a negative impact on some, we hope this disruption will be small and short lived."