Diagnosis Flashcards
What are different types of diagnostic errors?
Omission
Inadequate synthesis
Wrong formulation
Premature closure
What is sensitivity?
positive can only be max when the no. of false negatives are very small
What is meant by specificity?
Negative is maximal when there are vanishingly few false positives
How is specificity optimised?
Test is cut off in order to minimse false positives
How is sensitivity maximised?
Shift to the right to minimise false negatives
What is meant by prevalence?
The proportion of the given population that are “cases” during a specified time period
What happens if the prevalence of a disease is low?
The positive predictive value is low
What is the likelihood ratio?
Expresses the relationship between test accuracy and PPV
What does the likelihood ration tell us?
How many times more likely a positive test result is in someone with the disease compared to someone without the condition
What is an odds?
The probability of something being present divided by the probability of it being absent
What is important to consider when interpreting blood tests?
How the sample was taken and handled Random error Population distribution of values Context Biological variability
What is a spectrum bias?
If tests are initially tested on those severely affected
What is bayes theorem?
the probability of the event, based on prior knowledge of conditions that might be related to the event
What are the different types of bias in diagnostic testing?
Spectrum bias
Verification bias
Information bias
