Chapter 11: Screening for Disease Flashcards

1
Q

What is mass screening?

A

Also called pop. screening. Refers to the screening of total pop.groups on a large scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is selective screening?

A

Also called targeted screening. Applied to subsets of the pop. at a high risk for disease or certain conditions as the result of family history, age, or previous exposures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is screening?

A

examination of a group of usually asymptomatic individuals to detect those a high probability of having or developing a disease
-Secondary prevention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Uses of screening?

A
  • detect cases (to test in patients for cancer, etc.)
  • control of disease
  • research
  • education
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What makes a good screening?

A
  • Simple: easy to learn
  • Rapid: quick to administer and get results
  • Inexpensive: good cost ratio benefit
  • Safe: no harm to participants
  • Acceptable to target group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Validity?

A

Accuracy
-the ability of a test to predict if a person has the disease or not; a true measure
Valeria was accurate about the test she performed on herself. She had Leukemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Reliability?

A

Precision. Consistency
-the ability of a test to give consistent results when performed more than once on the same person under the same conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Types of validity?

A
  • Content
  • Criterion referenced
  • Construct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Measurement error?

A

constant errors introduced by a faculty measuring device and tend to reduce the reliability of measurements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Halo Effect?

A

the influence upon an observation of the observer’s perception of the characteristics of the individual observed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Social desirability effect?

A

Someone answers in a way that is agreeable w/ other people

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sensitivity?

A

the ability of a test to correctly identify those w/ the disease or condition (true positives)
-high sensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Is there a difference between screening and diagnosis?

A

Yes. Screening tests evaluate an individual’s risk of developing a genetic condition, while diagnostic tests identify genetic conditions.

  • Positive screening results are followed by diagnostic tests to confirm actual disease
  • Screening is more of testing on an individual to see if there is a disease inside of them.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Types of screening?

A
  • Mass screening
  • Selective screening
  • Multiphasic screening
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Mass screening?

A

Screening on a large scale of total population groups, regardless of risk status, usually for research or surveillance purposes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Selective screening?

A

Screening of selected groups of people in high risk categories

17
Q

Multiphasic screening?

A

Multiple screening tests together among a large group of people

18
Q

What are societal considerations of screening?

A
  • Condition should be important to the individual and the community
  • Favorable cost ratio benefit
  • High public acceptance of the test
19
Q

Scientific considerations?

A
  • Natural history of the condition should be understood properly
  • A knowledge base is good for prevention and occurrence of disease
20
Q

Ethical considerations?

A
  • The program can alter the natural history of the condition in a significant proportion of those screened
  • Suitable, acceptable tests for screening and diagnosis of the condition are available
  • Acceptable, effective methods of prevention are available
21
Q

Types of reliability?

A
  • Repeated measurement
  • Internal consistency
  • Interjudge
22
Q

What is repeated measurement reliability?

A

the degree of consistency among repeated measurements of the same individual on more than 1 occasion

23
Q

What is internal consistency reliability?

A

evaluates the degree of agreement or homogeneity

within a questionnaire measure of an attitude, a personal characteristic, or a psychologic attribute

24
Q

What is interjudge reliability?

A

reliability assessments derived from agreement among trained experts

25
Q

What is content validity?

A

The degree to which the measurement incorporates the domain of the phenomenon under study

26
Q

What is criterion-referenced validity?

A

Found by correlating a measure with an external criterion of the entity being assessed

27
Q

What is construct validity?

A

Degree to which the measurement agrees with the theoretical concept being investigated

28
Q

Are validity and reliability direct or inverse?

A

Inversely proportional

-when one goes up, the other is down

29
Q

Sensitivity?

A

The ability of a test to correctly identify those with the disease or condition (true positives)
-Formula: a/a+c

30
Q

Specificity?

A

The ability of a test to correctly identify those without the disease or condition (true negatives)
-Formula: d/b+d

31
Q

What is PPV?

A

Positive Predictive Value; PV+. The probability of having the disease if you test positive.

  • The proportion of people who screen + and truly have the disease
  • a/(a+b)
32
Q

What is NPV?

A

Negative Predictive Value; PV-. The probability of not having the disease if you test negative.

  • The proportion of people who screen - and truly do not have the disease
  • d/(c+d)
33
Q

Prevalence=?

A

those who were screened who have the disease

-(a+c)/(a+b+c+d)

34
Q

Accuracy? (efficiency)

A
  • those who were screened who received correct test results

- (a+d)/(a+b+c+d)

35
Q

If you have a fatal disease with no treatment (such as

Creutzfeldt-Jakob disease), optimize what? Why?

A

Specificity; b/c

36
Q

If you are screening to prevent transmission of a preventable disease (such as screening blood donors), optimize what? Why?

A

Sensitivity;

37
Q

Lead time bias?

A

The perception that the screen-detected case has longer survival because the disease was identified early

38
Q

Length bias?

A

Tumors identified by screening are slower growing and have a better prognosis.

39
Q

Selection bas?

A

Motivated participants have a different probability of disease than do those who refuse to
participate.