EPB finalINTRANET Flashcards
What is pre-test probability?
Prevalence.
What is prevalence?
Number of new cases within the population at risk.
How is pre-test probability (prevalence) different from incidence?
New cases among the population at risk.
What is an alpha and a beta error?
Alpha- false positive. Beta- false negative.
What is sensitivity?
Describes positivity in disease.
What will sensitivity help rule?
When negative helps rule a diagnosis out.
What is specificity?
describes negativity in health.
What will specificity help rule?
When positive helps rule a diagnosis in.
How is sensitivity calculated?
Proportion of true + in those with the disease.
Sensitivity is like what analogy?
Metal detector.
How is specificity calculated?
Proportion of true - in those without the disease.
What is the goal of applying a test to a patient?
To estimate post-test probability.
What is used to more quickly determine post-test probability?
LR.
LR are better used where?
In a clinical setting.
What is a LR+?
Proportion of patients with disease who have a particular finding divided by the proportion of patients without the disease who have the same finding.
What will a large + LR mean?
the larger the LR+ is the better to rule in the disease.
What is a LR-?
The proportion of patients with disease lacking a physical sign divided by the proportion of patients without the disease who also lack the same sign.
What will a small LR- mean?
The smaller the LR- the better to rule out a disease.
What is the old school way of using LR?
Nomogram.
What are the requirements to combine LR?
Findings must be independent of each other, and you can only combine LR of up to 3 independent tests.
How are LR combined?
Make the post-test probability of first test the pre-test probability of the second independent test.
What is the clinical prediction rule?
Clinical experience can be used to determine if a test is independent of another one.
How often are Predictive values used?
A lot in diagnostic literature, but not commonly used clinically.
What is PPV?
Proportion of those who test positive who actually have the disease.
What is NPV?
Proportion of those who test negative who actually have the disease.
What should be inculded when stating a parameter?
CI.
What makes a CI more reliable?
The narrower it is.
What is Kappa?
A statistical measurment of inter-examiner reliablity of a test.
What will a kappa of .7 mean?
there is a 70% better reproducability between examiners than by chance alone.
What Kappa scores are considered a good test of reproducability?
.6 or higher.
