Exam 2: Diagnostic Testing I and II Flashcards
What is a diagnostic test?
A generic term for any procedure to categorize the nature or severity of a condition
A procedure to classify a thing as normal or not normal or further classify as to origin or severity
What does serology typically refer to?
Assessment of serum antibody concentration (a measure of immune response to exposure
What provides evidence of an immune response?
Antibody titer
Why are titers done?
Desire to look at immune response to vaccination
Desire to look at immune response with inoculations
If titers are low, exposure is low; If titers are high, exposure is high indicating some type of disease
Look at examples and listen to lecture capture for diagnostic testing I because this is confusing
Look at examples and listen to lecture capture for diagnostic testing I because this is confusing
What is accuracy?
A measure of how close a test result is to the truth
The proportion of all correct tests out of the total number of tests run
What is accuracy affected by?
Prevalence
Sensitivity
Specificity
What is precision?
How close the measured values are to each other
What is sensitivity?
The ability of a test to correctly identify those that have the disease
What will highly sensitive test have?
A low number of false negatives
What is specificity?
The ability of a test to correctly identify those that do not have the disease
What will highly specific tests have?
Low numbers of false positives
What can cause a false negative?
Natural or induced tolerance Improper timing Improper selection of test Non-specific inhibitors Antibiotic induced immmunoglobulin suppression Incomplete or blocking antibody Analytically insensitive tests
How do you calculate sensitivity?
True positives / true positives + false negatives
What can cause a false positive?
Cross-reaction Non-specific inhibitors Non-specific agglutinins Contamination Vaccination cross reaction
