SCREENING AND PUBLIC HEALTH SURVEILLANCE Flashcards
The presumptive ID of an unrecognized disease or defect
by the application of tests, examinations or other
procedures that can be applied rapidly
screening
Mainly used to identify asymptomatic individuals
screening
Assumption: Earlier diagnosis leads to earlier treatment
screening
- Asymptomatic individuals
- Less accurate
- Less expensive
- Not a basis for treatment
screening
- Symptomatic individuals
- More accurate
- More expensive
- Basis for treatment
diagnostic
Characteristics of a Disease Appropriate for Screening:
- Disease is serious with severe consequences
- Treatment is more effective at an earlier stage
- Disease has a clinical detectable preclinical stage
- The preclinical phase is fairly long and prevalent in the target
- population
Characteristics of a Screening Test:
- Economical
- Convenient
- Relatively free of risk and discomfort
- Acceptable to a large number of individuals
- Highly valid and reliable
Screening programs should
be conducted efficiently,
with minimal inconvenience
and discomfort and at a reasonable cost
feasibility
Screening programs should achieve its goal of reducing morbidity and mortality
effectiveness
Potential systematic errors of screening:
- Volunteer bias
- Lead-time bias
- Length bias
interval between the time of disease detection through screening and the time of disease recognition in the absence of screening
Lead Time
phenomenon where early diagnosis of a disease falsely makes it look like people are surviving longer.
lead time basis
phenomenon whereby slower-growing, less aggressive tumors have a longer preclinical screen-detectable
period and are therefore more likely to be screendetected than faster-growing, more aggr
Length Time Bias
Types of Screening:
- Mass screening
- Targeted screening
- Opportunistic screening
- Multiphasic screening
screening for general population
mass screening
scrrening for high-risk population
targeted screening
screening for case-finding
opportunistic screening
