hoppe Flashcards
chronic
once you have it stays
acute
it comes and goes
prevalence
proportion of persons in a given population that has a particular condition. Number of cases divided by total population
incidence
rate at which new cases arise with a given population.
sensitivity
Accuracy of the screening procedure to correctly identify all individuals in a population who have a particular disorder
sensitivity calculation
A/(A+C) * 100= sensitivity
specificity
Accuracy of the screening procedure to correctly identify those who do not have the disorder
specificity calculation
D/(D+B)= specificity
sensitive tests
Few false-negatives
For serious but treatable conditions
Use early to rule out disease
Test people without complaints
specific tests
Few false-positives
For conditions with serious consequences for misdiagnosis
Use to rule in disease
Confirm a suspected diagnosis
high sensitivity and low specificity leads too?
To make sure that you detect 100% of the “cases” you will refer a lot of false positives
Over-referrals
high specificity and low sensitivity leads too?
To make sure that you don’t “mislabel” or “stigmatize” anyone with a misdiagnosis, you will miss a lot of true positives
Under-referrals
Positive predictive value
Probability that someone who fails the screening really does have the disorder
positive predictive value calculation
A/(A+B)
negative predictive value
Probability that someone who passes the screening really does NOT have the disorder
negative predictive value calculation
D/(C+D)
Yield
A measure of the previously unrecognized cases that are treated as a result of implementing the screening procedure
Requires tracking and follow-up of referrals
retinomax over referral to under referral ratio?
43.3% to 7.5%
sure sight over referral to under referral ratio?
68% to 5%
snellen E over referral to under referral ratio?
64% to 14
MCT over referral to under referral ratio?
9% to 0.9%
