Screenings in Medicine

Question 1

What are two questions that patients should ask physician when a medical screening test is recommended?

Answer 1

1. how accurate is the screening test you are about to recommend for me?
2. When the test results are announced, how confident will you be in prediction of whether I do or don’t have the disease

Question 2

What is a true positive positive?

Answer 2

test correctly reports to positive result in a patient that actually does have the disease

Question 3

What is a true negative?

Answer 3

test correctly reports a negative result in a patient that actually does not have a disease

Question 4

What is a false positive?

Answer 4

test incorrectly reports a positive result in a patient that actually does not have the disease

Question 5

What is a false negative?

Answer 5

test incorrectly reports a negative result in a patient that actually does have the disease

Question 6

What is sensitivity?

Answer 6

how well a test can detect presence of disease when in fact disease is present

Question 7

What is the sensitivity proportion?

Answer 7

true positive / all diseased x 100

Question 8

What is specificity?

Answer 8

how well a test can detect absence of disease when in fact the disease is absent

Question 9

What is the specificity proportion?

Answer 9

true negative / all not disease x 100

Question 10

What describes the accuracy of prediction of disease based on known test results?

Answer 10

positive predictive values

negative predictive values

Question 11

What is positive predictive values (PPV)?

Answer 11

how accurately a positive test predicts the presence of disease

Question 12

What is the PPV proportion?

Answer 12

True positive / all positive tests x 100

Question 13

What is the negative predictive value (NPV)?

Answer 13

how accurately a negative test predicts the absence of disease

Question 14

What is the NPV proportion?

Answer 14

True negative / all negative tests x 100

Question 15

What is diagnostic accuracy/ diagnostic precision (DA/DP)?

Answer 15

proportion of total screenings that a patient is correct identified as either having a disease or not having a disease with either a positive or negative test, respectfully

Question 16

What is the DA/DP equation?

Answer 16

(true negative + true positive) / (all patients) x 100%

Question 17

What is likelihood ratios (LR)?

Answer 17

ratio of the probability of a give test result for a person with disease / probability of the same rest result for a person without disease

Question 18

What is the likelihood ratio positive (LR+)?

Answer 18

probability of a positive test in the presence of disease / probability of a positive test in the absence of disease

Question 19

What is the LR+ equation?

Answer 19

sensitivity / (1- specificity)

Question 20

What is likelihood ratio negative (LR-)?

Answer 20

probability of a negative test in the presence of disease / probability of negative test in absence of disease

Question 21

What is the LR- equation?

Answer 21

(1-sensitivity) / specificity

Question 22

LR+ should be ____ to demonstrate the test is most beneficial

Answer 22

> 10

Question 23

LR- should be ____ to demonstrate the rest is most beneficial

Answer 23

<0.1

Question 24

What is validity?

Answer 24

ability to accurately discern between those that do and those that do not have the disease

Question 25

Validity is analogous to ______

Answer 25

precision

Question 26

What is internal validity?

Answer 26

extent to which results accurately reflect what was being assessed (true situation of study population)

Question 27

What is external validity?

Answer 27

extent to which results are applicable to other populations (not included in OG study, also known as generalizability)

Question 28

What is reliability

Answer 28

ability of a test to give the same result on repeated uses

Question 29

What is a valid test always?

Answer 29

reliable, but a reliable test is not always valid

Question 30

What is a type I error

Answer 30

False positive

Question 31

What is a type II error

Answer 31

False negative