Posted by Sten Westgard, MS
One of the outcomes of the Milan 2014 meeting was a set of "Task-Finishing" groups that were assigned various aspects of the Milan Mandate (more commonly known as the 1st EFLM Strategic Conference Consensus Statement, or EFLM-SCCS, which can be pronounced, 'ee-effle-em-sucks').
EFLM-SCCS established that there were now 3 models for setting quality specifications, rather than the 5 levels of the Stockholm Consensus Hierarchy that had been established in 1999. This was hardly radical, as it mostly involved merging 3 levels into the lowest form of model, "state of the art".
But what was a true advancement for the field was the recognition that not all tests were going to be able to use the highest, best, or most ideal model for setting performance specifications. That is, some methods like HbA1c can have their performance specifications defined by the clinical use (model 1), but other methods aren't so clearly understood or clinically applied. So we face a future, finally realistic, where some tests will have biologically-based (model 2) goals, and other tests will have clinical-use-based (model 1) goals, and all the rest will have state of the art based goals (model 3). It's going to be a heterogeneous world. Between 1999 and 2014, there had been increasing pressure to use the biologic-based goals (also known as the "Ricos goals"), but evidence had been mounting that the Ricos goals were sometimes too wide, sometimes too narrow, for the methods on the marketplace. Indeed,the EFLM is in the process of revamping the entire database with much more statistical rigor (which is why there hasn't been an update since 2014).
So we have accepted that there will be different goals, and different goal models, for different analytes.
But who gets to choose the goal, the model, for each analyte?
As it happens, the EFLM has designated a group to do just that, and their preliminary findings have been published:
Criteria for assigning laboratory measurands to models for analytical performance specifications defined in the 1st EFLM Strategic Conference, Ceriotti F, Fernandez-Calle P, Klee GG et al, CCLM 2017;55(2):189-194.
This publication doesn't give the assignment of the analytes to the appropriate models, but it does describe the criteria which will be used to decide how to assign each analyte to a model.
In other words, it's not the beginning of the end, but it's the end of the beginning.
The paper does provide some example goal model assignments:
- whole blood HbA1c is the Model 1: outcome-based
- plasma Uric acid is Model 2: biologic variation-based
- urine Sodium is Model 3: state of the art
After three years of effort, it's good to see the progress of the task finishing group. One only hopes it won't be another three years before we see the final list.
A final point to be made is that the criteria note that they are not final, but temporary. Since biologic variation data, clinical use, and even the state of the art are not stationary concepts, these model assignments will evolve over time. What may only be assigned a state of the art model today may eventually graduate to a higher model assignment in the future.
We'll just need to develop some specifications on how often we need to revisit the specifications for assigning specifications...
[P.S. I have a bad attitude about this. I'm not trying to be disrespectful to the EFLM or the committee task group, they are all extremely smart individuals and far more qualified than me to do this work. The paper is a thorough, well-written argument and definitely worth your attention. But it just seems like this is taking a long time. We may be generating lots of material for papers and conferences and abstracts, etc. but we look like we're moving at glacier speed.]