Use of cut‐off values on the limits of quantification reported in datasets used to estimate dietary exposure to chemical contaminants

left-censored data, limit of quantification, analytical results, chemical contaminants, dietary exposure
First published in EFSA Supporting Publications
20 July 2018
4 June 2018
Technical Report


The analytical data on the presence of chemical contaminants in food and feed used in dietary exposure assessments in EFSA scientific outputs often contain a high number of left‐censored data, i.e. non‐quantified/non‐detected data; EFSA usually uses the so‐called substitution method to make use of this type of data in its assessments. However, the presence of left‐censored data together with a wide range of detection and/or quantification limits is often an important source of uncertainty associated with the dietary exposure estimates. This Technical Report describes a step‐wise approach to select the most appropriate cut‐off values on the provided censoring limits based on: 1) legal requirements; 2) typical expanded uncertainty levels; or 3) distributions of the quantified values and reported limits of quantification. This approach is intended to minimise the influence of left‐censored data on the uncertainty associated with the dietary exposure estimates.

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