General Practice and Population Healthcommon
A new screening blood test for a cancer has a sensitivity of 90% and a specificity of 95%. It is proposed for use in the general population aged 50–74, in whom the prevalence of the cancer is 1%. A 58-year-old woman with no symptoms has a positive result and asks what this means.
Of every 100 people in this population who test positive, approximately how many actually have the cancer?