Screening Tests Flashcards
(22 cards)
What is true positive?
Patient tests positive + has the disease
What is false postiive?
Patient tests postiive but doesnt have disease
What is false negative?
Patient tests negative but has the disease
What is true negative?
Patient test negative and doesnt have disease
What is sensitivity?
Proportion of those with the condition who have a postiive test result
Sensitivity equation
True positive / all with disease
What is specificity?
Proportion of patients without the condition who have a negative test
Specificity quation
True negative / all without disease
What is positive predictive valve
Proportion of people with positive result that actually have the condition
Positive predictive valve equation
True positive / all postiive test
What is negative predictive valve?
Proportion of people with negative test who dont have the condition
Negative predictive valve equation
True negative / all negative test
What is likelihood ratio for positive test result?
How much the odds of the disease increase when test is positive
Likelihood ratio for postiive test result equation
Sensitivity / 1-specificity
What is likelihood ratio for negative test result?
How much the odds of disease decreased when a test is negative
Likelihood ratio for negative test result equation
1-sensitivity / specificity
What is absolute risk?
Risk of acquiring given disease over time
What is absolute risk difference?
Absolute risk in exposed - AR in unexposed
How to calculate odds ratio?
Odds of exposure in case
—————————————
Odds of exposure in control
How to calculate risk ratio
Risk of exposed
————————
Risk of unexposed
How to calculate odds of exposure
No. of exposed
————————
No. of unexposed
What does it mean if the correlation coefficient (r) is:
- 1
- 0
- -1
- 1: strong positive correlation
- 0: no correlation
- -1: strong negative correlation
