Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
40 Cards in this Set
- Front
- Back
|
VALIDITY
|
the ability of a test to detect who does and does not have disease
|
|
|
SENSITIVITY
|
the ability of a test to ID correctly who has the disease of interest
|
|
|
SPECIFICITY
|
the ability of a test to ID correctly those who do not have the disease of interest
|
|
|
RELIABILITY/REPRODUCTIBILITY
|
extent to which results obtained by a test are replicated if the test is repeated
|
|
|
WHAT IS THE KEY ASSUMPTIOIN FOR SCREENING?
|
early detection leads to a more favorable prognosis
|
|
|
Screening is more like a ____ test that tells you whether you should go on for another test or not.
|
crude
|
|
|
When you screen people for disease, are they symptomatic or asymptomatic?
|
asymptomatic
|
|
|
Why do we screen participants?
Name 3 reasons. |
1. to favorably modify the natural history of disease
2. improve morbidity 3. reduce mortality |
|
|
Disease with _____ consequences are appropriate for screening.
|
serious
|
|
|
Disease where tx is given ____ sxms is more beneficial than tx given ____ are more appropriate for screening.
|
before, later
|
|
|
Disease where prevalence of detectable preclinical disease is ____ in population to be screened is more appropriate for screening.
|
high
|
|
|
Name 6 characteristics that make a screening test suitable.
|
1. inexpensive
2. easy to administer 3. well-tolerated 4. valid 5. reliable 6. reproducible |
|
|
Draw example of 2x2 screening table.
Explain in a legend what a,b,c,d represent |
Early Disease ("truth") (top)
Screening Test (side) a b c d a= true positives b=false positives c=false negatives d=true negatives |
|
|
PREDICTIVE VALUE POSITIVE
|
probability of having disease given you have a positive screen
|
|
|
PREDICTIVE VALUE NEGATIVE
|
probability of not having disease given you have a negative screen
|
|
|
Maximize sensitivity at expense of specificity then you:
Decrease false ______, but yield false _______ |
negatives, positives
|
|
|
Choose to increase sensitivity when penalty for not identifying cases is ____
|
high
|
|
|
choose to increase sensitivity when disease is _____.
|
serious
|
|
|
choose to increase sensitivity when _______.
|
treatment exists (if it doesn't exist, do you want to know you have disease?)
|
|
|
choose to increase sensitivity when _______.
|
disease can be spread
|
|
|
choose to increase sensitivity when _______.
|
subsequent dx has minimal costs and risks
|
|
|
choose to ____ specificity when penalty for incorrectly identifying someone as case is ____
|
increase, high
|
|
|
Name 3 ways that we can assess whether the screening program works or not.
|
1. follow up with those who tested positive
2. assess cost per case detected 3. asses how many of those who test positive have the disease (PV+) |
|
|
PV+ is influenced by _____, _____, and ______ of the detectable preclinical phase of the disease.
|
sensitivity, specificity, prevalence
|
|
|
PV+ is most influenced by ____ and ____
|
sensitivity, prevalence
|
|
|
How do you increase prevalence?
|
target populations at high risk
|
|
|
Name 3 biases specific to screening.
|
1. volunteer
2. lead-time 3. length |
|
|
VOLUNTEER BIAS
|
people who choose to be screened will be different from those who do not.
these people are usually healthier with lower mortality rates "the worried well" |
|
|
LEAD-TIME BIAS
|
cases detected by screening appear to survive longer due to their earlier dx
|
|
|
what does lead-time mean?
|
the duration by which the diagnosis of disease is moved forward in time among each case detected by the screening program
|
|
|
LENGTH BIAS
|
cases with a longer detectable preclinincal phase and thus a more favorable prognosis tend to be overrepresented among screen detected cases
|
|
|
BASIC PRINCIPLES OF MASS SCREENING:
Condition should be _______. |
an important public health issue
|
|
|
BASIC PRINCIPLES OF MASS SCREENING:
should be accepted ____ for pts with disease |
effected treatment
|
|
|
BASIC PRINCIPLES OF MASS SCREENING:
if no tx, then ____ |
do not screen
|
|
|
BASIC PRINCIPLES OF MASS SCREENING:
adequate ____ and ___ facilities should exist |
dx, tx
|
|
|
BASIC PRINCIPLES OF MASS SCREENING:
Natural history of condition should ___ understood |
reasonably be
|
|
|
BASIC PRINCIPLES OF MASS SCREENING PROGRAMS:
it should be ID in ____ or ___ sxm stage |
latent, early
|
|
|
BASIC PRINCIPLES OF MASS SCREENING PROGRAMS:
Should (not be/be) invasive |
not
|
|
|
BASIC PRINCIPLES OF MASS SCREENING PROGRAMS:
Screenigns hould be a ________ rather than a _____ program--people get upset if it's taken away |
continuing process, temporary
|
|
|
BASIC PRINCIPLES OF MASS SCREENING PROGRAMS:
Screening program shoul dbe shown to be effective in reducing ____, ____ from the disease--though this isn't always the case |
morbidity,mortality
|
