Enter the pre-test probability and the likelihood ratio into the calculator to determine the post-test probability.

## Post-Test Probability Formula

The following equation is used to calculate the post-test probability.

Pre Test Odds = P/(1 – P) = 0.012

Post Test Odds = Pre Test Odds * LR

Post Test Probability = Post Test Odds/(1 + Post Test Odds)

• Where P is the pre-test probability
• LR is the likelihood ratio

## Post-Test Probability Definition

Post-test probability is defined as the chance of an event occurring given a pre-test probability and pre-test odds.

## Post-Test Probability Example

How to calculate Post-Test Probability?

1. First, determine the pre test odds.

Calculate the pretest odds.

2. Next, determine the likelihood ratio.

Calculate the likelihood ratio.

3. Finally, calculate.

Calculate the post-test probability using the formulas above.

## FAQ

What is post test probability?

A post-test probability is a likelihood for an event to occur given a starting pre-test probability, and pre-test odds.