TORREGROZA-DIAZGRANADOS, Eduardo de Jesús. Diagnostic tests: Probability Ratios. []. , 36, 3, pp.403-410.   14--2021. ISSN 2011-7582.  https://doi.org/10.30944/20117582.717.

The usefulness of a diagnostic test is quantified by calculating the probability measures and the probability ratio measures. Probability measures are sensitivity, specificity, positive predictive value, and negative predictive value. Sensitivity and specificity are used to choose the best test to use, among several available; however, they cannot be used to estimate the probability of a certain disease in a particular patient. In clinical practice it is essential to know what is the probability that a patient with a positive result in a diagnostic test will present the disease and what is the probability that a patient with a negative result in a diagnostic test will not present the disease. The positive and negative predictive values ​​provide us with the answer to this question, however, it depends both on the sensitivity and specificity, and on the prevalence of the disease in the study sample. Probability ratio measures also describe the performance or usefulness of a diagnostic test and possess two important properties: they summarize the type of information that sensitivity and specificity, and they can be used to calculate the probability of disease after a positive or positive test. negative. The purpose of this publication was to define the concept of probability ratio measures, expose its main strengths, and explain how probability ratio measures are calculated when the test of interest expresses its results dichotomously, in more than two categories or ordinally.

: diagnosis; diagnostic techniques and procedures; laboratory test; probability; likelihood ratio.

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