SCREENING IN DISEASE CONTROL

Question 1

SCREENING
•_______________ of unrecognized disease or defect by ____________, ________ or other procedures

Answer 1

Presumptive identification

application of tests, examinations

Question 2

SCREENING

• Is in the _______ level of prevention. For early _________ and ________

Answer 2

second

detection and treatment

Question 3

Rationale for screening

–___________ will lead to better treatment

Answer 3

early diagnosis

Question 4

Screening

• To sort out individuals who ____________________ from ______________

Answer 4

probably have the disease

Those who do not

Question 5

Screening is intended to be diagnostic

T/F

Answer 5

Not intended to be diagnostic

Question 6

In screening, Those who test positive are sent for ____________ to ___________

Answer 6

further evaluation to determine whether they do have the disease.

Question 7

Benefits of screening

• Results used to estimate __________ of a condition in a given population
• Detect disease in individuals who are ___________
• Usefull where you have ______ medical facilities. As it can cover _________________

Answer 7

prevalence

apparently well

poor; large proportion of community

Question 8

Criteria for mass screening of population

• Disease must be an __________________ problem- prevalence, consequence
• There should be an _________________ for patients with recognized disease.

• Treatment given before symptoms should _____________ than that given after symptoms develop.
• Facilities for __________ and _______ should be available

• Should be early recognizable pre symptomatic stage of disease

Answer 8

important public health

acceptable treatment

reduce morbidity and mortality

diagnosis and treatment

Question 9

criteria for mass screening of population

• Should be suitable test that is ________ and ______ to the population
•_______________ of the disease should be understood

• there Should be agreed policy on ________________
•Cost of screening should ___________________ when disease is detected

• Screening should be a _______ exercise

Answer 9

acceptable and easy to administer

Natural history

whom to treat as a patient

not outweigh cost of providing medical care

continuous

Question 10

Criteria for evaluating performance of screening test
• ________
• ________
• ___________

Answer 10

Reliability
• Validity
• Yield

Question 11

Reliability

Ability of test to yield _____________________________ (______________)

Answer 11

consistent results when performed more than once under the same set of conditions.

repeatability

Question 12

Reliability

Influenced by ;
1. Lack of _________ of instruments

2. Lack of ___________ which results from observer(s) usually due to ________________ procedures and definitions

Answer 12

precision

objectivity

un- standardized

Question 13

reliability

Influenced by:

3. Lack of __________ – characteristic being measurement has changed.
4. Lack of ___________ – due to use of different instruments or test kits. Different results n same person

Answer 13

constancy

congruency

Question 14

Validity
Ability of test to ___________________

Answer 14

measure the characteristic we intend to measure

Question 15

Validity

1. Sensitivity- the ability of the test to yield _________ results in individuals (with or without?) the disease
2. Specificity – the ability of test to yield _________ results in individuals (with or without?) the disease

Answer 15

positive ; with

negative ; without

Question 16

Validity
• Sensitivity = (___________)* 100
• Specificity = (___________) *100

• a = TP (True positive)
• b= FP (False positive)
• c= FN (False Negative)
• d= TN (True Negative)

Answer 16

a /a +c

d/b +d

Question 17

validity
• A test which is highly sensitive will have (low or high?) false negative result
• A test which is highly specific will give (low or high ?) false positive results

Answer 17

Low

Low

Question 18

Yield

• Amount of _______________ which is identified as a result of screening

Answer 18

previously unrecognised disease

Question 19

Yield

Yield affected by
1. _________
2. Prevalence of _________ disease
3. _________ of _________ screening
4. _________________ of population

Answer 19

Sensitivity

Prevalence of preclinical disease

Extent of previous screening

Health behaviour of population

Question 20

Combination of tests
• Combine different test to have _______________________ in test
• Can combine test in ———- or test in ________

Answer 20

high degree of confidence

series

parallel

Question 21

Combination of tests

Series – don’t consider individual positive unless _____________. This helps to _________

• Parallel – all administered __________ and person __________________ is considered positive

Answer 21

positive in series of tests

reduce FP.

at same time

with positive result on any

Question 22

Evaluation of screening programmes

• Use __________,_________ and _______ study designs
• ___________ – cost effectiveness, diagnosis and treatment of those who test positive, yield
• _________ to population -time, comfort

•_________ value – measures whether or not an individual actually has the disease given the results of the screening tests

Answer 22

descriptive , analytical and experimental

Feasibility

Acceptability

Predictive

Question 23

Evaluation

• Positive predictive value- probability that a person ____________ given that ________________. Shows the proportion of positive results that are ________

• Negative predictive value - Proportion of negative results that are ___________.

Answer 23

actually has the disease

he or she tests positive; truly positive.

truly negative

Question 24

Evaluation
• Positive predictive value
____/_________ =(a/a+b)

• Negative predictive value -
___/_________= (d/c+d)

Answer 24

TP/TP+FP

TN/TN+FN

Question 25

evaluation
• Effectiveness-reduction in ____________

Answer 25

morbidity and mortality

Question 26

evaluation

• Lead time –interval between the ____________________ and when ___________________________

Answer 26

diagnosis of a disease at screening

it would have been detected due to development of symptoms