Diagnostic Test and Screening Flashcards
An external source of truth regarding the disease status of each individual population
Gold standard
Compare result of test of interest (index test) with those of the reference standard (gold standard)
Classic diagnostic test accuracy studies
Looking for a suspected condition which is tested for or confirmed or excluded
Diagnostic
Investigation of exposed people, to sort the ex[psed and ill from the exposed and well
Case finding
No specific exposure or indication that the individual has the disease
Screening
Characteristic of a good screenign test
- Valid (Sensitive and specific)
- Reliable (consistent results, no random errors)
- Yield (number of cases identified per thousand screened)
- cost benefit
- acceptable
- follow up services
Extent to ehich the test measures what is its supposed to measure
Validity
Ability of the test to distinguish between who has the disease and who has not
Validity
Reproducibility / Repeatability
Reliability
Stability or consistency of information
Reliability
Similar information is supplied when measurements are performed more than once
Reliability
Amount of previously unrecognized disease and brought to treatment as a result of screening
Yield of screening program
Identify those who have the disease
Sensitivity
Does not have disease
Specificity
Less expensive, less invasive, less unconfortable
those with positive perform the second test
Sequestial testing
