| Term | Definition |
|---|
| screening test | used to identify disease before it's clinically apparent. should be acceptable to pt, inexpensive, be able to be done at a time that can impact survival. ex: mammogram, colonoscopy |
| diagnostic test | used to reliably classify pts into those that have the disease and those that don't. done in context of individual pt (history, PE, prevalence, epidemiologic pattern, etc.). ex: fasting blood glucose (FBG), TSH |
| prognostic test | predict outcomes that help clinician make decisions or decide how to communicate information to pt. ex: EKG for diabetes- how likely to develop renal failure or cardiovascular disease? |
| what might be a test to 'monitor disease activity' in diabetes? | hemoglobin A1C. note that screening and diagnostic tests may be used to monitor disease activity. other ex: PSA level (prostate CA) |
| pre-test probability | probability of the target disorder before the results of a diagnostic test are known (subjective estimates, prevalence, clinical prediction rules estimates) |
| gold standard | standard for diagnosing a disease to which all other diagnostic tests are compared. may be invasive, expensive, risky, or painful. ex: CT scan for pancreatitis. oral glucose tolerance test for diabetes (vs. FBG) |
| prevalence | proportion (percentage) of individuals in a population who have the disease |
| sensitivity | proportion of pts who HAVE the disease who have a POSITIVE test. (sensitivity is 100% if you at least identify all pts w/ the disease) |
| specificity | proportion of patients who DO NOT HAVE the disease who have a NEGATIVE test. (100% specificity if at least identify all pts who don't have the disease) |
| true positive | correctly classified as having a disease |
| false negative | incorrectly classified as NOT having disease |
| true negative | correctly classified as NOT have disease |
| false positive | incorrectly classified as having disease |
| sensitivity and specificity provide information of the ___ of a test | diagnostic accuracy. should be consistent w/ similar patients and similar setting |
| positive predictive value and negative predictive value provide information about the ___ of a test | utility. prevalence will affect PPV and NPV! (if prevalence decreases with sensitivity staying the same, PPV will decrease (-> test may become useless) and NPV will increase) |
| positive predictive value | indicates percent of pts with a positive test that actually have the disease |
| negative predictive value | indicates percent of pts w/ a negative test that do NOT have the condition |
| adjusting a cut-off point in a diagnostic test with continuous results in a tradeoff between ___ and ___ | sensitivity and specificity (i.e. healthy pts may falsely test positive, but miss less ppl who have the disease (sensitivity dec., specificity inc.)) |
Combine with other sets
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