Sensitivity and Specificity

Question 1

Sensitivity

Answer 1

› Probability that a subject with the
disease will screen positive

Question 2

Specificity
›

Answer 2

Probability that a subject who is disease
fee will screen negative

Question 3

Not dependent on

Answer 3

Populations

Question 4

Sensitivity equation

Answer 4

TP/TP+FN

Question 5

Specificity equation

Answer 5

TN/TN+FP

Question 6

SPin and SNout

Answer 6

SPin
* A Specific tes,t if it is Positive rules a disease
in
* A very Specific test rules In disease
SNout
* A Sensitive test, if it is Negative rules a
disease out
* A Sensitive test helps rule the disease out
Evidence-Based Dentistry –Boston - 2012

Question 7

Predictive Value for a positive
result (PV+)

Answer 7

PV+ asks “ If the test result is positive what is
the probability that the patient actually has
the disease?”
PV+= true positive/(true positive + false
positive)

Question 8

Predictive Value for a negative
result (PV-)

Answer 8

PV- asks “ If the test result is negative what is
the probability that the patient does not
have disease?”
PV-= true negatives/(true negatives +false
negatives)