A Practical Device for the Application of a Diagnostic or Prognostic Function

Abstract

The application of a diagnostic or prognostic Multiple Logistic Function (MLF) in medical practice may, depending on the complexity of the model, require considerable arithmetic. Various methods for the elimination of such arithmetic, e.g. sets of tables or nomograms, have been proposed. An alternative method of eliminating the necessary arithmetic is described here. It is based on the principle of the familiar slide-rule. As an example, the design of a slide-rule for the evaluation of a diagnostic model for acute myocardial infarction is described. The slide-rule method allows for the evaluation of logistic models with complex linear combinations in the exponent. Adequate devices can be produced at low cost.