Testing for Diagnosis and Screening Flashcards Preview

Contemporary Practice of Medicine > Testing for Diagnosis and Screening > Flashcards

Flashcards in Testing for Diagnosis and Screening Deck (19)
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1
Q

Sensitivity and specificity

A

Sens - percentage of people who do have a disease that test positive

Specificity - percentage of people that DO NOT have the disease that test positive

2
Q

Screening and confirmatory tests

A

Screen - maximize sensitivity

COngirm - maximize specificity

3
Q

Advantages of sequential testing

A

Lowers overall sensitivity and raises specificity

4
Q

How does prevalence change

A

Higher prevalence - means great PPV

Lower prevlaence - means lower PPV and higher NPV

5
Q

Likelihood ratio

A

Used to asses value of a given diagnostic test

6
Q

Positive and negativel ikleihood ratio

A

Sensitivity/1-specifcity for positive

1-sensitivity/specificity for negative likelihood

Can use Fagan nomogram

7
Q

Strong moderate and weak

Also unhelpful

A

Strong - 10-infinity or .1 to 0

Mod - 5-10 or .1 to .2

Weak - 2 to 5 or .2 to .5

.5-2 is generally unhelpful

8
Q

Diseases that can be screened

A

Important health problems (high incidence or mortalitiy)
Tx more bebenficial in early stages compared to later
Early dx impoves QOL or survival

9
Q

Appropriate screening tests

A

Simple, safe, and precise
Can detect the latent or early sx stage
Beneift outweight physical or psych harm

10
Q

Screening benefits

A

Disease incidence or mortality
NNS
Increase in life expectancy (standard is over 1 month gain)…avoid screening if life expectancy less than 10 years

11
Q

Screening harms

A

Adverse effects of screening
Overdx of disease
False positive screening tests

12
Q

Screening program rationale

A

Cost is balanced in relation to expenditures
Systematic plan for monitoring program
Participant edu about benefits and disadvantages

13
Q

Simultaenous testing

A

Screening test emphasis on sensitivity and sacrifice PPV

Cotesting will raise sensitivity and lower specificty

14
Q

Overdiagnosis bias

A

Makes it look like mortality lower because we are including people who were asymptomatic in the orginal group…you find the true positives who are asymptomatic

15
Q

LEad time bias

A

Outcome is the same but it looks like the survived with the disease longer because the diagnosis was made earlier in their life

Could artificially inflate the benefit of the results

16
Q

Length bias

A

Due to different types of diseases

Will capture more slowly progressive cases than rapidly progresing

17
Q

All ture positives and negatives

A

Maximizes sensitivity while minimizing specificty

18
Q

Clinically meaningful ositives and negatives

A

Minimizes sensitivity while maximizing specificty

19
Q

RCTs vs cohorts

A

Cohorts - healthy used

RCTs - outcome should be cancer mortality in the overall population and NOT survival or cancer case fatality rate