screening test

Question 1

screening test

Answer 1

procedure which enables to predict the absence or presence of a disease from knowledge of test results

Question 2

2 dimensions of screening tetsts

Answer 2

appropriateness to detect the disease
diagnostic power

Question 3

biomarker

Answer 3

a measure that tells us information about a disease

Question 4

criteria for using a screening test

Answer 4

• the significant burden of a disease in a population
• the preclinical stage is detectable and prevalent
• early detection improves outcome
• acceptable to population, inexpensive and relatively accurate

Question 5

requirements for screening test to identify biomarkers

Answer 5

• test must be quick, easy, and inexpensive
• must be safe for patients, physicians
• sensitivity, specificity, and predicted values must be known and acceptable
• adequate follow up for screened positive

Question 6

aim of screening tests

Answer 6

-minimise the probability of error
-maximise the probability of true positive and true negative

Question 7

false discovery rate (alpha)

Answer 7

FDR= 1-PPV

Question 8

what happens as the prevalence of a disease increases

Answer 8

the PPV of the test increases and the NPV decreases

Question 9

curva ROC

Answer 9

finding a threshold= optimal combination of specificity and sensitivity

Question 10

purpose of ROC

Answer 10

1. finding optimal threshold- optimal point
2. finding optimal test type

Question 11

screening level

Answer 11

how good the test discriminated is proportional to subarea

Question 12

screening level equation

Answer 12

z= AUC= 0.5/squareroot sigma2AUC