Tag Archives: AST

“The end of Clinical Breakpoints as we know them?…””


During the ASM conference in Boston, I attended a couple of talks on the process of anti-microbial susceptibility testing (AST). There are really only two main players (a duopoly of sorts) left standing with regards to setting standards for AST. These are the Clinical & Laboratory Standards Institute (CLSI) and the EUropean Committee on Anti-microbial Susceptibility Testing (EUCAST).

Representatives from each organisation spoke during the conference sessions. Reading between the lines,  I did not get the impression that a unification of the two organisations was imminent, mainly because I did not detect any warmth between the respective speakers…

There was considerable discussion on the setting of Clinical Breakpoints. Clinical Breakpoints are necessarily a “messy” compromise between Epidemiological Cut-off values (ECOFFs), pharmaco-kinetic & pharmaco-dynamic (PK-PD) data, and most importantly, clinical response. As long as this model continues, EUCAST and CLSI committees will continue to tinker with and argue about the breakpoints, but in the painful knowledge that a single value can never be agreed upon as being a definitive answer. There are just too many variables.

The problem is therefore ripe for an app-based solution…

I foresee a future in anti-microbial susceptibility testing where the main variables are taken much more into account than they currently are.

I see the time when all the microbiology laboratory will do will be to provide an organism identification and  MIC values for a restricted number of key antibiotics.

The clinician will then take his smartphone app, enter this lab information, but also add in key patient variables such as site of infection, renal function & body mass index, and degree of immunocompromise.

The app will then process all these variables together and give for each antibiotic the likelihood of clinical response of a certain antibiotic, not only for this particular organism, but for this particular patient.

And thus there will no longer be a need for concrete/single value clinical breakpoints, but rather the focus will be on personalising the lab information to each particular patient.

I can see such apps for MIC interpretation being developed in the next few years. 

And if I were a lead member of NCCLS or EUCAST I would be recruiting the services of a good IT applications specialist on to the steering committee, and sooner rather than later…