Screening Flashcards
What are the 3 ways of detecting disease?
Spontaneous presentation
Opportunistic case finding
Screening!!!!!!!!!!!!
What is the definition of screening?
A systematic attempt to detect an unrecognised condition via the application of tests and other procedures that are rapid and effective
What is the aim of screening?
IT IT NOT TO FIND SOMETHING EARLIER
It is to improve a patients outcomes compared to finding something the usual way
What are the 4 criteria for a screening program?
- CONDITION must be an important health issue: understood epidemiology, detectable early stage with cost effetive intervention
- TEST must be simple, safe, precise, valid and acceptable to patients
- TREATMENT must be effective and evidence based
- PROGRAMME should be based on high quality RCT evidence. It should be cost effective and be of positive benefit.
What are the current UK (NHS England) screening programmes? There are 11….
Diabetic retinopathy Newborn and infant physical exam AAA Bowel ca. Breast screening Cervical screening Fetal abnormality Infectious diseases in pregnancy Newborn blood spot Newborn hearing SCD and thalassaemia
What is sensitivity?
Proportion of actually diseased people who test +ve
What is specificity?
Proportion of actually healthy people who test -ve
What is PPV?
Probability that someone who tests +ve actually has the disease
What is NPV?
Probability that domino who tests -ve is actually healthy
What is lead time bias?
It may look like people are living longer, but in fact they die at the same time. They are just diagnosed earlier so appear to have had the disease for longer
What is length time bias?
Screening tends not to be used for aggressive diseases, so gives the false impression it it more useful than it is
What are some sociological critiques of screening?
Victim blaming Individualising pathology Mass surveillance Morality Most screening is targeted at women
