Segars: Screenings in Medicine Flashcards
1
Q
What does a patient want to be told when they get screened for a disease?
A
-The truth!
2
Q
What 2 questions should patients ask their physician when a medical screening test is recommended?
A
- how accurate is it?
- When the test results are announced, how confident will you be in your prediction of whether I do or don’t have the disease?
3
Q
What is true positive?
A
- test is positive and the patient does have the disease
- Box A
4
Q
What is False positive?
A
- test is positive but the patient does not have the disease
- Box B
5
Q
True negative
A
- negative test
- pt doesn’t have the disease
- box D
6
Q
False negative
A
- negative test
- but the pt does have the disease
- box C
7
Q
What will the numerator be?
A
-either box A or D
8
Q
What is sensitivity and specificity related to?
A
-the test itself
9
Q
What does positive or negative predicitive values do?
A
- predicts the accuracy of diagnosis (based on known test result)
- remember, boxes A and D are the numerators
10
Q
What is sensitivity
A
- how well a test can detect preence of disease when in fact it is truly present
- proportion of time that a test is positive in a pt that is known to have the disease
- TP/(everybody that has disease)*100%
11
Q
What is specificity?
A
- how well a test can detect absence of disease when in fact it is truly absent
- proportion of time that a test is negative in pt that is known to not have the disease
- TN/(all non-diseased… like TN and FP)*100%
12
Q
What is a positive predictive value (PPV)?
A
- how accurately a positive test predicts the presence of disease in a pt with a positive test result
- proportion of true positives in a pt that tests positive (correct prediction)
- PPV=TP/(all positive tests)
- A/(A+B)
13
Q
What is negative predictive value (NPV)?
A
- how accurately a negative test predicts the absence of disease ina pr with a negative test result
- proportion of true negatives in a pt that tests negatvie (correct prediction)
- NPV= (TN/(All negative tests))
- C/(C+D)
14
Q
What is Diagnositc accuracy/diagnostic precision?
A
- Proportion of patients that are correctly identified as either having truly having disease (TP) or truly not having disease (TN) out of all pts screened
- (TP+TN)/(all patients)*100%
15
Q
How do we figure out if it is a column total or row total that we will be dealing with?
A
