Learning objectives

  • - Gold standard
  • - Test accuracy, including sensitivity, specificity and likelihood ratio
  • - Prevalence, and effects on positive and negative predictive values
  • - Pretest and posttest probabilities

A patient has bleeding gums. You want to use the best diagnostic tool to evaluate the periodontal disease.

There are several possibilities:
(1) use a periodontal probe
(2) use X-rays
(3) use microbiological tests

What is the best diagnostic tool measurement?