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Flashcards in Segars: Screenings in Medicine Deck (17)
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1

What does a patient want to be told when they get screened for a disease?

-The truth!

2

What 2 questions should patients ask their physician when a medical screening test is recommended?

-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

What is true positive?

-test is positive and the patient does have the disease
-Box A

4

What is False positive?

-test is positive but the patient does not have the disease
-Box B

5

True negative

-negative test
-pt doesn't have the disease
-box D

6

False negative

-negative test
-but the pt does have the disease
-box C

7

What will the numerator be?

-either box A or D

8

What is sensitivity and specificity related to?

-the test itself

9

What does positive or negative predicitive values do?

-predicts the accuracy of diagnosis (based on known test result)
-remember, boxes A and D are the numerators

10

What is sensitivity

-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

What is specificity?

-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

What is a positive predictive value (PPV)?

-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

What is negative predictive value (NPV)?

-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

What is Diagnositc accuracy/diagnostic precision?

-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

How do we figure out if it is a column total or row total that we will be dealing with?

-with sensitivity or specificty, there will be something about absolute truth... column totals
-

16

What is validity?

-getting it right.... telling the truth
-getting it in boxes A and D

17

What is reliability

-ability of a test to give the same result on repeated uses
-a valid test is always reliable, yet a reliable test is not always valid