|
| |
|
Sensitivity
and Specificity |
| Sensitivity
is the ability to correctly identify those who have the
disease.
Specificity
is the ability to correctly identify those who do not
have the disease.
Ideally, a test should have 100%
sensitivity and 100% specificity. In other words, the test always
correctly identifies the disease state of the people tested.
|
| Result
of Screening |
Disease
State |
| Disease |
No
Disease |
| Positive |
true
positive |
false
postive |
| Negative |
false
negative |
true
negative |
|
| People
who have the disease are the "true positives."
People who do not have the disease are the "true
negatives."
Sensitivity
= ( "true positives" divided by ("true
positives" + "false negatives") ) multiplied by
100 (to make it a percentage)
When the
"false negatives" is a small number relative to the "true
positives", sensitivity approaches 100%.
Specificity
= ( "true negatives" divided by ("true
negatives" + "false positives") ) multiplied by
100 (to make it a percentage)
When the
"true negatives" is a small number relative to the "false
positives", specificity approaches 100%.
|
| Back
to MedAnth 101 |
MedAnth
Home |
| |
|