Division 7.3.3

Calculation as mean value of bioanalytical results (in BEQ, corrected for blank and recovery) from multiple analysis of samples (n ≥ 6) contaminated at two-thirds of the maximum or action level. This is based on the observation that this level will be around the cut-off determined under point 7.3.1 or 7.3.2.

Calculation of cut-off values based on a 95 % level of confidence implying a false-compliant rate < 5 %, and a RSD_R < 25 %:

1. 1..

   from the lower band of the 95 % prediction interval at the decision limit of the confirmatory method,

2. 2..

   from multiple analysis of samples (n ≥ 6) contaminated at the decision limit of the confirmatory method as the lower endpoint of the data distribution (represented in the figure by a bell-shaped curve) at the corresponding mean BEQ value.