Lab Medicine Flashcards
Accuracy
how closely the test results correspond to the “gold standard”
Precision
how reproducible the results are with repeat testing of the same specimen
Specificity
among people without the disease, how often is the test right used to rule IN disease
Sensitivity
among people with the disease, how often is the test right used to rule OUT disease
Predictive value
estimation of the probability of the presence or absence of the disease
Positive predictive value
percentage of the person with a positive test result & have the disease
Negative predictive value
percentage of persons with a negative test result & don’t have the disease
Prevalence
number of cases of a disease in a population
Positive likelihood ratio formula
Sensitivity / (1 - Specificity)
Negative likelihood ratio formula
(1 - Sensitivity) / Specificity
Likelihood ratio
if >1, indicates the test result is associated with the disease: if
Posttest probability
the likelihood a patient has a disease after getting a positive test result; takes into account the likelihood ratio and prevalence
Sensitivity formula
TP / (TP + FN)
Specificity formula
TN / (TN + FP)
Positive predictive value (PV) formula
(TP / TP + FP) x 100 = %
