ebmlecture8and9

Question 1

what are diagnostic tests used for

Answer 1

screening people or a population, followup with patients,

Question 2

what are the disadvantages of diagnostic testing

Answer 2

can be expensive, can risk morbidity or mortality, can be uncomfortable.

Question 3

how do you asses validity in diagnostic testing

Answer 3

question clearly defined, did it confirm/deny as well as gold standard, did it evaluate on the correct spectrum,

Question 4

what is sensitivity

Answer 4

screening people or a population, followup with patients, snNout test with high sensitivity is negative the condition is rules out.

Question 5

what is specificity

Answer 5

how well does a test find people without the condition, spPin if test with high specificity is positive rules the condition IN

Question 6

a good test increases the _____ test probability significantly

Answer 6

post test probability. = post test odds /post test odds +1

Question 7

what is Baye’s theorem

Answer 7

the probably that an individual has a disease is directly related to the prevalence in the entire population.

Question 8

what is positive predictive value

Answer 8

true positive over false positive

Question 9

what is negative predictive value

Answer 9

true negative over false negative

Question 10

what are likelihood ratios

Answer 10

predicts the likelihood of a certain result in a patient with the target disorder compared to one without it. LR greater than 1 increases the probability.

Question 11

how do you asses validity in therapy studies

Answer 11

clear research question, groups randomized, all subjects accounted for, participants blinded, treatment equal otherwise, comparable groups.

Question 12

what is concealed allocation

Answer 12

when the clinicians and patients do not assign groups or know assignments, helps to avoid selection bias.

Question 13

what is the confidence intervals

Answer 13

reported at 90 95 and 99%. states how confident they are that the mean will be in a certain range. For example the treatment group had a 5% higher survival rate then CI would be -1.2–+12 note that when the line crosses 1 it makes the results of the test not valid.

Question 14

what is the ARR absolute risk rate

Answer 14

the controlled events rates over the experimental group events rates

Question 15

what is the NNT number needed to treat

Answer 15

1/ AAR the higher the NNT the worse. The number of patients you would have to treat to obtain one good result or to avoid one bad result