LPC was developed within a project funded by the Italian Ministry of University through the following stages:
- Review of literature to identify all the possible critical points in Legionella control;
- Classification of all selected critical points in three independent areas of interest: management, water distribution system and patient susceptibility;
- Identification of several critical points for each area;
- Split of each critical point into items to be answered in form of questionnaire;
- Classification of items through a multidisciplinary consensus into 4 risk categories (1 - best practice/low to no risk, 2 - possible Legionella presence (not evidence based)/medium risk, 3 - probable Legionella presence (evidence based)/high risk, 4 - demonstrated Legionella presence/very high risk);
- Analysis of the 3 areas scores in order to define a general risk score and a structure related risk score;
- Use of a risk matrix (including a feasibility score to be assigned by local practitioners linked to the setting) to define final priorities.