Clinical Reasoning Flashcards
What is sensitivity?
The ability of a test to correctly identify those with the disease (true positive rate) and expressed as a %.
This is the proportion of people who test positive out of all those who do have the disease.
Sensitivity is measuring how delicate a test is; the more sensitive, the better it is at picking up tiny changes. The higher the sensitivity, the better negative test is for ruling out disease. But a highly sensitive test can create a lot of false positives (as these aren’t taken into account in the calculation of sensitivity).
What is specificity?
the ability of a test to identify those without the disease (true negative rate) expressed as a %
This is the proportion of people who test negative of those who do not have the disease.
So it is only looking at the disease absent column.
If a test is very specific, it’s good at ruling disease in (SPin).
What is a positive predictive value?
The probability that the disease is present if the test is positive
What is a negative predictive value?
The probability the disease is not present if the test is negative
What is a likelihood ratio in diagnostic testing?
LRs are basically a ratio of the probability that a test result is correct to the probability that the test result is incorrect.
What is a negative likelihood ratio in diagnostic testing?
The probability of a person who has the disease testing negative divided by the probability of a person who does not have the disease testing negative.
