Clinical breakpoints and dosing of antibiotics

25 January 2020

Clinical breakpoints - breakpoints and guidance

Before using the EUCAST 2020 breakpoint table - make sure you read this.

There are many changes in the breakpoint tables v. 10.0 (2020). Some may be difficult to understand or accept without having followed the evolution and consultations on the changing definitions of the susceptibility categories , especially that of the old intermediate (I), still designated I but now "Susceptible, increased exposure". As a result of this, some species and agents are never categorised “Susceptible, standard exposure” (S), only “Susceptible, increased exposure” (I). To make sure these are never reported S, an arbitrary breakpoint of S ≤0.001 mg/L (corresponding to S≥50 mm). These are meant to be off-scale and not part of testing. For these, include concentrations to reliably distinguish between I and R.

 Users of the tables are urged to inform themselves on definitions of S, I and R, the use of the arbitrary, off-scale breakpoints and the fact that Pseudomonas aeruginosa, for many agents, is never reported S, only I, but is still possible to treat provided the dosing and mod of administration is considered.

Visit the section on new definitions of S, I and R, and read the first few tabs in the breakpoint table (Notes, Guidance, Dosage, Technical uncertainty). 

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Breakpoints published in Addendum during the year will be part of the next version of the full Clinical breakpoint tables valid from early January each year.

 

Previous versions of breakpoint tables:

Previous versions of breakpoint tables. 

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Definitions of clinical breakpoints and epidemiological cut off values

Modified definitions valid from 1 January, 2019.