Method for providing a reliable non-invasive diagnostic test of the presence and/or severity of a disease, and associated software and expert system includes:a. collecting a diagnostic index, called Initial Index, preferably a score,b. calculating the Dispersion Index of the collected Initial Index,c. analyzing the reliability of each data by identifying if at least one data of index collected in step a) is an abnormal, inconsistent and/or a non-homogeneous data, or is responsible for a greater decrease in the Dispersion Index than that observed with other data,d. if a data is an abnormal, inconsistent and/or non-homogeneous data, or a data lowering a Dispersion Index, generating an Event Alert,e. if an Event Alert is generated, calculating new indexes,f. replacing the Initial Index including an abnormal, inconsistent and/or non-homogeneous data or a data affecting the Dispersion Index, with an Alternative, Estimated or a Mixed Index.
