Response to Mark A. Mackay and Tony C. Badrick: on the holy grail of clinical chemistry

After the Milan Strategic conference in 2014 a consensus statement was published on analytical performance specifications (APS), revising the Stockholm consensus of 1999. One of the task and finish groups (T&F) groups that were started was one on the total error (TE) concept. Several issues did need to be resolved concerning TE and the measurement uncertainty (MU) models. Most importantly were flaws in the model for calculating the permissible (or allowable) TE. These models are based upon biological variation to derive APS, the second model of the Milan consensus.