MedCalc: Bayesian Analysis Model

Enter PREVALENCE, SENSITIVITY, and SPECIFICITY:

PREV: SENS: SPEC:


Or enter TP, FN, TN, and FP:

Disease No Disease
Positive Test TP: FP:
Negative Test FN: TN:

Positive Predictive Value =
Negative Predictive Value =
Positive Likelihood Ratio = Pre-test Probability =  (prevalence)
Negative Likelihood Ratio = Post-test Probability =


Remember:
Sensitivity = TP / (TP+FN)
Specificity = TN / (FP+TN)
Prevalence = (TP+FN) / (TP+FN+FP+TN)
Predictive value positive = TP / (TP+FP)
Predictive value negative = TN / (FN+TN)
Positive Likelihood Ratio = SENS / (1-SPEC)
Negative Likelihood Ratio = (1-SENS) / SPEC

Pre-test Probability = Prevalence
Pre-test Odds = Pre-test Prob / (1 - Pre-test Prob)
Post-test Odds = Pre-test Odds x Likelihood Ratio
Post-test Probability = Post-test Odds / (1 + Post-test Odds)


Created by: Charles Hu, Ron Kneusel & Gary Barnas M.D.
Created: Saturday, January 15, 2000
Last Modified: