Diagnostic Tests

Question 1

what are diagnostic tests for

Answer 1

helping you rule in or out particular medical and physical problems in order to reach a diagnosis

Question 2

what signals PTs when doing a special test

Answer 2

provocation of symptoms
pain in an area
abnormal signs or symptoms

Question 3

why are diagnostic tests important

Answer 3

informing patient care and evaluating treatment benefit

Question 4

how do diagnostic tests inform patient care

Answer 4

accurate diagnosis informs the selection of the most appropriate treatment

Question 5

why are diagnostic tests for PTs

Answer 5

primary care providers that may be in a situation to make a diagnosis

Question 6

what are three things that you want to know about a special test

Answer 6

are they reproducible/accurate
how often do they affect clinical decision making
do they have adverse effects

Question 7

highly sensitive tests will

Answer 7

produce many true positives and false positives

Question 8

highly specific tests will produce

Answer 8

less false positives and more true negatives

Question 9

what is a true positive

Answer 9

diagnostic test is positive in those with the diagnosis

Question 10

what is a true negative

Answer 10

diagnostic is negative in those without the diagnosis

Question 11

what is a false positive

Answer 11

diagnostic test is positive in those without the diagnosis

Question 12

what is a false negative

Answer 12

diagnostic is negative in those who have the diagnosis

Question 13

diagnostic tests that have high sensitivity are good at

Answer 13

identifying true positives in a large sample

also will produce many false positives due to low trigger threshold

Question 14

what are highly sensitive tests used for

Answer 14

ruling out a problem or rejecting possible diagnosis

Question 15

highly specific tests identify ____

Answer 15

identifying true negatives due to high trigger threshold

also will produce many false negatives

Question 16

what are highly specific tests good for

Answer 16

rule in a problem or confirm a diagnosis

Question 17

when is a diagnostic test result clinically useful

Answer 17

test with high sensitivity having a negative result

test with high specificity having a positive result

Question 18

what is a positive likelihood ratio

Answer 18

ratio of the likelihood of positive result in someone with the disease to the likelihood of that result in someone without the disease

Question 19

what # of likelihood ratio means what

Answer 19

2-5 = small likelihood of positive
5-10 = moderate likelihood of positive
>10 = conclusive for confirming patho

Question 20

what is a negative likelihood ratio

Answer 20

ratio of the likelihood of a negative result in someone with the disease to that of the result in someone without the disease

Question 21

what negative likelihood ratio means what

Answer 21

0.2-0.5 = small likelihood of absence
0.1-0.2 = moderate likelihood of abs
<0.1 = conclusive in the absence of patho

Question 22

what is the positive predictive value

Answer 22

probability that the patient truly has disease if there is a positive diagnostic test

Question 23

how to calculate ppv

Answer 23

of true pos + # of false pos

number of true positives / (number of true positives + number of false positives)

Question 24

what is negative predictive value

Answer 24

probability that the patient does not have the disease if they have a negative test

Question 25

how to calculate negative predictive value

Answer 25

number of true negative / number of false + true negatives

Question 26

what is pretest probaility vs post test probability

Answer 26

probability that a patient has the pathology before/after a diagnostic test is conducted

Question 27

if there is a higher incidence of pathology then

Answer 27

there will be a higher pre-test probability of pathology being present

Question 28

when using a cluster, what happens to diagnostic accuracy

Answer 28

increases greatly