# step II

 The flashcards below were created by user hartman.elizabeth on FreezingBlue Flashcards. Sensitivity finds disease ...best used to screen Excludes disease if test negative, Includes disease is test is positiveTP/TP+FN Specificity How good in normal populationused to confirm diseaseTN/TN+FP Reference interval +/- 2SD = 95% of normal Negative Predictive Value How likely the negative result is a true negative and not a false negative- with a 100% sensitive test = 100% b/c there are no false negatives-with a 100% specific test = could be TN or FN does not exclude disease-TN/TN+FN Highly sensitive test ...increases prevalance of disease Increasing upper limit of normal of a test reference interval increases specificity and PPVdecreases sensitivity and NPV decreasing upper limit of normal on test reference interval increases sensitivity and NPVdecreases specificity and PPV Prevelance Prevelance = incidence x durationTP+FN/ TP+FN+TN+FP -prevelance is how many people have the disease right now. It increases as the duration of a disease increases. -incidence is how many people develop a disease in a population over a set time, usually one year. Positive predictive value how likely a positive result is a true positive -TP/TP+FP-100% sensitive test = result could be TP or FP includes people with disease but does not confirm-100% specificity = 100% b/c there is no false positives, confirms disease! Authorhartman.elizabeth ID23975 Card Setstep II DescriptionHY fact review Updated2010-06-18T02:14:53Z Show Answers