3 - HaDSoc - Screening + The NHS Flashcards
What is the purpose of screening?
- Detect an unrecognised condition using tests to rapidly distinguish between apparently well people who probably have the disease, and those who probably don’t
- To give a better outcome compared to finding the disease in the usual way
What are the 4 Wilson/Younger criteria for having a screening programme?
1) Disease/condition
- Severe/freq, early detectable stage
2) Test
- Simple, safe, precise, valid, acceptable to pop, cut-off point
3) Treatment
- Effective, evidence-based, early tx advantageous
4) Programme
- Quality assured, facilities for counselling, diagnosis and treatment available, cost-benefit analysed
Regarding screening tests, what is meant by sensitivity?
Probability a case will test positive
Regarding screening tests, what is meant by specificity?
Probability a non-case will test negative
Regarding screening tests, what is meant by positive predictive value?
Probability someone who tested positive, actually has the disease
Regarding screening tests, what is meant by negative predictive value?
Probability someone who tested negative, actually doesn’t have the disease
How is the sensitivity of a screening test calculated?
Number of true positive results /
Number of true positives + false negatives
How is the specificity of a screening test calculated?
Number of true negative results /
Number of true negatives + false positives
How is the positive predictive value of a screening test calculated?
Number of true positive results /
Number of true positives + false positives
How is the negative predictive value of a screening test calculated?
Number of true negative results /
Number of true negatives + false negatives
Why is it important for a screening test to have high sensitivity?
If it wasn’t sensitive, a larger number of people would receive a false negative result:
- Inappropriate reassurance, may lead to delay of presentation when symptoms appear
Why is it important for a screening test to have high specificity?
If it wasn’t specific, a larger number of people would receive a false positive result:
- Stress
- Anxiety
- Inconvenience
- Costs
What are the critiques of screening?
- Alters patient-doctor relationship (doctor turns people into patients, rather than them presenting to dr)
- Hard to define targeted group to screen
- Evaluation is susceptible to lead time bias, length time bias and selection bias
- Harms caused by inevitable false results
- Victim blaming - individual must take responsibility
- Interfering ‘nanny state’ - people are expected to present
- Social norms - judged if you do not present
What year was the NHS created, and on which 3 principles was it initially based on?
1948
1) Universal
2) Comprehensive
3) Free
What main reforms have occurred in the NHS since it was created?
- 1980 - ^ management to improve quality
- Commissioning based on needs, quality and cost
- 2012 - Heath + Social care act - power to primary care providers
- Devolution between England, Scotland, Ireland + Wales
- ^ Marketisation
