Flashcards in Screenings in Medicine Deck (21)
What two questions should you, as a patient, ask your physician before consenting to a test?
How accurate is the test?
How confident are you as a physician in the determining my disease status after results are in?
True Positive in Box
True Negative in Box
False Positive in Box
False Negative in Box
The the word accurate in the patient's first question is determined by...
Sensitivity (Should ideally be 100%)
Compared to gold standard
What is Sensitivity?
The degree of accuracy that a test can correctly detect presence of disease in those that are known to have disease.
What is specificity?
The degree of accuracy that a test can correctly detect absence of disease in those that are healthy.
A high sensitivity test has a low ____ and a high specificity test has a low ___.
false negative rate
False positive rate
True Positive / (true positive plus false negative)
Denominator all disease
True negative / (true negative and false positive)
The confidence in a physician's interpretations is determined by
Positive Predictive Value
Negative Predictive Value
Positive predictive value determines
how accurately the positive test predicts presence of disease
Negative predictive value determines
how accurately the negative test predicts the absence of disease
Calculating positive predictive value
True Positive / ( true positive and false positive) or all positives
Calculating negative predictive value
True negative / ( true negative and false negative) or all negatives
The more frequent a disease is in the community, _____
the easier it will be to find that disease in that community
As prevalence changes, ____ doesn't change but ___ changes
Accuracy of a test (sensitivity)
Diagnostic Accuracy is ___
Proportion of total screenings that a patient is correctly identified as either having disease or NOT having disease
TN + TP / (Total Pop)
If diagnostic accuracy is 100%, no presence of FN or FP
Likelihood Ratio Positive
Positive ratio of Disease / Ratio of Non-diseased positive
TP/ Total Pop Dx // FP/ Total Pop healthy