2.6 Disaggregated

Last, data should be collected and stored at the highest possible resolution and never aggregated (summarised into a group or class) in the database. Any aggregation for analysis or presentation should come at a later stage. For example, when disc diffusion is used to assess antimicrobial sensitivity of a bacterial strain, the inhibition zone diameter should be recorded as a quantitative, raw value in the database. The classification as resistant or susceptible may then be derived from the recorded diameters, on the basis of the accepted cut-off values (taken from international standards such as the European Committee on Microbial Susceptibility Testing, EUCAST [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] or the Clinical Laboratory Standards Institute, CLSI). Should these cut-off values change, you can then review the raw data and update if necessary. This is not possible if only aggregated data (for example, only that classification of ‘resistant’ or ‘susceptible’) is recorded.