Likelihood ratios and probability of infection in a tested individual

Input Values

  

Use this to calculate positive and negative likelihood ratios for a test of given sensitivity and specificity and to calculate the post-test probability of infection, given the pre-test probability and test performance. For these calculations, the pre-test probability of disease is the estimated of probability of infection based on clinical signs and any other (such as previous test results) available information. If no other information is available the estimated prevalence of disease in the population of origin should be used. The post-test probability of disease is the same as the positive (or negative) predictive value for the test for the specified pre-test probability of disease.

Pre-test probability (prevalence):
Test Sensitivity:
Test Specificity:

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