Everything Session 8 (Screening) Flashcards
What is the definition of screening?
Presumptive identification of unrecognised disease or defect via examination
If tests are positive further diagnostic tests done
What is the purpose of screening?
Prepare
Management
Plain in advance to reduce overall cost and burden
What are the 5 screening criteria areas?
-The condition
-The test
-The intervention
-The screening programme
-Implementation
What are the criteria for The Condition for Screening?
Must be an important health problem with known epidemiology, incidence, prevalence and history
All cost effective primary prevention has been implemented
What are the criteria for The Test for screening?
Test needs to be simple, safe, precise and valid
The cut off value is defined and agreed
There must be an agreed policy on further diagnostic investigation
What are the criterias for the screening programme of screening?
Needs to have proven effectiveness reducing mortality/morbidity
Evidence the screening programme is clinically, socially, and ethically acceptable
The benefits must outweigh the harm (over diagnosis, false positives)
The COST needs to be economically balanced
What are the criteria for implementation of screening?
All other management options have been considered
Needs adequate staffing and facilities for screening
Patients need to make their own informed choice
What are the 3 difficulties in evaluating screening programmes?
-lead time bias
-length time bias
-selection bias
What is lead time bias?
It is where early diagnosis appears to prolong survival however patients who are earlier diagnosed live the same time as someone who isn’t, they just live knowing they have the disease
What is length time bias?
Screening programmes are not good at picking up aggressive and sudden diseases
They are good at picking up slow growing things that may not cause an issue
Wha is selection bias?
When screening studies are skewed by healthy volunteers
Those who attend engulf screening are likely to attend other screening programmes and participate in other positive Health elated behaviours
Informed consent is required for all screening programmes? What does a lay person need in order to make and informed decision?
Benefits communicated
Harms and risks of the prevention communicated
Person has the capacity to understand and weigh up these benefits and risks
What are the 3 risks/types of error that come with screening?
False positives
False negatives
Over diagnosis
What is a false positive testing error?
Healthy individuals ho don’t have the disease are falsely referred for further investigation
What is a false negative testing error?
Unhealthy individuals who have the disease are told that they are healthy
