Division 7.3.3 F1

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 level or action threshold, based on the observation that this level will be around the cut-off value determined under point 7.3.1 or point 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 end-point of the data distribution (represented in the figure by a bell-shaped curve) at the corresponding mean BEQ value.