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About CLSI



ECOFFinder is a MS Excel spreadsheet calculator that is freely available to the public. It is designed to estimate epidemiological cutoff values (ECVs, ECOFFs) for the MICs or MECs of wild-type bacterial or fungal populations. It follows the methodology described in “Turnidge J, Kalhmeter G, Kronvall G. Statistical characterisation of bacterial wild-type MIC value distributions and the determination of epidemiological cut-epidemiological cut-off values. Clin Microbiol Infect 2006; 12:418-25.” Instructions for use are provided on the first sheet.

Which version do I need? Due to the peculiarities of MS Excel, three versions are provided: one for releases of Excel prior to 2010 (ECOFFinder XL 2003), one for releases of Excel from 2010 onwards (ECOFFinder XL 2000+), and one for Mac computers (ECOFFinder XL 2011 for Mac). Make sure that you enable macros when asked by Excel to do so.

ECOFFinder for Excel Prior to 2010


ECOFFinder for Excel After 2010


ECOFFinder for Excel 2011 for Mac


Whatever version you use, you will need to enable the Add-in “Solver” (where to do this varies depending on the version of Excel). Also, if you have enabled Solver and you get a runtime error the first time you use it, close and then re-open Excel to see if that fixes the problem.

For any issues or questions, contact John Turnidge (author):

If you are looking for RangeFinder, click here.



× 7 = thirty five

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