DTA Flashcards
What is a diagnostic test accuracy study
Study that looks at how well a test identifies or rules out a disease (sensitivity and specificity)
What is the importance of DTA study
To see if a new test is useful or harmful
What question do we use in DTA instead of an PICO
PITR
What does PITR stand for
Patient
Index test
Target disorder
Reference standard
What is an index test
The test that we are interested in testing
What is a reference standard
The test that is most accurate
What are the types of errors that can occur in a diagnostic test
False positive
False negative
What is a false positive
Someone that does not have the disease presents as having it
What is a false negative
Someone that has the disease presents as not having the disease
What is the formula for sensitivity
TP/(TP+FN)
What is the formula for specificity
TN/(TN+FP)
What is sensitivity good at
Ruling out conditions
What is a high specificity good at
Ruling in conditions
What are the 3 types of bias that can occur in a DTA study
Spectrum bias
Review bias
Verification bias
What is spectrum bias
People that have diseases that are hard to diagnose have been excluded out of the study
What is review bias
The index test is not blind to the reference standard and vice versa
What is verification bias
When patients do not receive both index test and reference standard so this leads to under and over estimation
What are the disadvantages of a bad diagnostic test
Over treatment
Unnecessary anxiety and pain of procedure
What questions do you need to think about to apply the result of a DTA study to your patients and setting?
- was there a clear study question
- is the study population spectrum similar to patients in practise
- can the index test be applied in the same way in your healthcare setting
- does the target condition match the condition you want to identify
