Random facts (epidemiology, etc) Flashcards
1
Q
Define sensitivity
A
- The likelihood of a positive test result in a patient affected with the disease (a true positive)
- Higher the sensitivity, the lower the false negative rate (so if they test negative, it’s believable)
- Used to RULE OUT a disease (screening test)
2
Q
Define specificity
A
- The likelihood of a negative test result in a patient not having the disease (true negative rate)
- Higher the specificity, the lower the false positive rate (so if they test positive, it’s believable)
- Used to CONFIRM a diagnosis
3
Q
Define positive predictive value
A
- The chance that a patient with a positive test result has the disease
- Good confirmatory tests
- Usually correlates with specificity when the disease prevalence is low
4
Q
Define negative predictive value
A
- The change that a patient with a negative test result does not have the disease
- Good screening tests
- Usually correlates with sensitivity when the disease prevalence is high
5
Q
What do PPV and NPV depend on?
A
Disease prevalence