Screening Flashcards
Differentiate between passive and active surveillance
Passive - provider initiated, under reported
Active - health department initiated; more accurate
The use of tests, exams, and other procedures to identify unrecognized (subclinical) disease among those who are apparently well
Screening
T/F?
Screening is used on those that are showing signs and symptoms of a health problem.
Diagnostic tests are done when someone is beginning to show signs or symptoms of a disease.
When should screening be done?
1) disease must be serious and have public health consequences
2) disease must have a preclinical phase that can be ID’d through screening
3) DPCP should be prevalent and have a long duration
4) early treatment must be more effective than later treatment
Validity
How close a measurement is to true state of nature
Reliability
Agreement between multiple measurements on the same sample
What are validity and reliability assessed with?
validity - sensitivity, specificity, PPV, NPV
reliability - kappa statistic, percent agreement
Differentiate between false negative and false positive.
False negative - shows that you are not diseased, but you actually are
False positive - shows that you have the disease, but you actually don’t
Positive Predictive Value
Proportion of people with a positive test who have disease
Negative Predictive Value
Proportion of people with a negative test who are actually healthy
Specificity has a greater impact on (negative/positive) predictive values
Sensitivity has a greater impact on (negative/positive) predictive value.
positive, negative
Percent Agreement
The proportion of observations where two or more readers agree
Kappa Statistic
measure of agreement between observers or measurements of the same categorical variable beyond the agreement due to CHANCE ALONE
Lead Time Bias
screened individuals may appear to live longer because disease was detected earlier in its progression
Volunteer Bias
those who decide to get screened may be different from those who do not (type of selection)
