Screening

Question 1

Validity/accuracy

Answer 1

Ability of a screening to test measure the actual value

Actual value measured is using gold standard

Question 2

Predictive value

Answer 2

Diagnostic power of a test

Question 3

PPV NPV

Answer 3

Positive predictive value
Probability of having a disease after a positive test

Npv
“ not having disease after negative test

Question 4

Diagnostic power of inclusion and exclusion

Answer 4

Inclusion- ppv

Exclusion- npv

Question 5

Reliability/repeatability/precision

Answer 5

Test will give same values when repeated in the same person under the same condition

Question 6

The different variations in reliability

Answer 6

Subject variation
Instrument variation
Observer variation

Question 7

Kappa’s coefficient

Answer 7

To measure degree of interobserver agreement

Question 8

Sensitivity And formula

Answer 8

Ability of the test to detect true positive
True positive divided by diseased positive

(Try to think what specificity is too :P)

Question 9

Ideal property of a screening test

Answer 9

Sensitivity

Question 10

PPV and prevalence relation

Answer 10

Directly proportional

Question 11

Npv and prevalence relation

Answer 11

Inversely proportional

Question 12

Ppv and fp relation

Answer 12

Inversely

Question 13

Sensitivity and specificity relation

Answer 13

Inversely proportional

Question 14

Which are the constant properties

Answer 14

Sensitivity and specificity
Inherent properties
Will not change with prevalence

Question 15

Parallel test describe

Answer 15

3 tests done together
Any 1 test positive- disease +
All 3 tests negative-disease -

Question 16

Sequential testing describe

Answer 16

2 tests done in sequence
1st test -ve - don’t repeat next test
1st test +ve -2nd test

Question 17

Know the relations of sensitivity/specificity/fp/fn/npv/fpv for parallel and sequential testing

Answer 17

You didn’t skip that did you -.-

Question 18

Likelihood ratio + -

Answer 18

LR+ sens/1-spec

LR- 1-sens/spec

Question 19

ROC curve

Answer 19

Receiver operating characteristic curve

To assess performance of a diagnostic test

Question 20

Area under curve in ROC

Answer 20

Performance,accuracy

Question 21

If disease fatality is more which parameter should be important

Answer 21

Increase sensitivity

Question 22

If treatment is costly and has more adverse effect which parameter should be involved

Answer 22

Increased specificity

Question 23

Lead time

Answer 23

Advantage gained by screening

Between point of detection and diagnosis

Question 24

Screening should be done between which points

Answer 24

B and C

If you’re super clueless pls check the notes

Question 25

How do we decide screening time

Answer 25

Based on critical point

Question 26

Prospective screening

Answer 26

Others are benefitted 
For communicable disease
Eg.hiv among prostitutes
Screening of immigrants 
COVID
TB

Question 27

Prescriptive screening

Answer 27

Own benefit 
NCDs
Eg.neonatal screening 
PAP smear 
Breast self examination