Lower Eval Week 2 Flashcards
What does screening do?
Begins to rule out many possible diagnoses
Reliability
Extent a test is free from error, uses the intraclass correlation coefficient
Intrarater reliability
Reliable for a single person
Interater reliability
Reliable for a group
Dichotomous Outcomes
Either positive or negative that the patient has the pathology
What value is used to adjust for chance in dichotomous outcomes
Kappa value
Validity
The test is actually testing what you want tested
QUADAS
Quality Assessment of Diagnostic Accuracy Studies
Specificity
Fraction of people without the disease that got a negative test
Highly specific tests will not give many false positives
SPIN
Specificity rules in a diagnosis
Sensitivity
Fraction of people with the disease that got a positive result
Highly sensitive tests will identify nearly everyone with the disease
SNOUT
A test with a high sensitivity that is negative will rule out a diagnosis
Likelihood Ratio
Index developed to describe how reliably a test detects a condition
Calculations of Likelihood Ratios
LR+ = Sensitivity/(1-Specificity) LR- = (1-Sensitivity)/Specificity
To rule IN a disorder
Want a high LR+