screening test Flashcards

1
Q

screening test

A

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

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2
Q

2 dimensions of screening tetsts

A

appropriateness to detect the disease
diagnostic power

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3
Q

biomarker

A

a measure that tells us information about a disease

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4
Q

criteria for using a screening test

A
  • 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
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5
Q

requirements for screening test to identify biomarkers

A
  • 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
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6
Q

aim of screening tests

A

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

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7
Q

false discovery rate (alpha)

A

FDR= 1-PPV

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8
Q

what happens as the prevalence of a disease increases

A

the PPV of the test increases and the NPV decreases

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9
Q

curva ROC

A

finding a threshold= optimal combination of specificity and sensitivity

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10
Q

purpose of ROC

A
  1. finding optimal threshold- optimal point
  2. finding optimal test type
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11
Q

screening level

A

how good the test discriminated is proportional to subarea

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12
Q

screening level equation

A

z= AUC= 0.5/squareroot sigma2AUC

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13
Q
A
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