English français

Home > Glossary > PCR and Diagnostics > Limit of detection

Limit of detection

The limit of detection (LOD) of an assay is the lowest quantity of a target sequence (template) that can be detected per analysis. In practice in Scanelis lab, the LOD is expressed in copies of target sequence (on the genome of the pathogen we are looking for).

For each assay developped by Scanelis, this threshold is determined in accordance with the European Pharmacopoeia recommendations and checked on each analysis series.
A statistical analysis on a high number of standards from different dilution ranges (minimum 24 determinations per quantity) is then performed to determine the LOD at the 95% level (Probit analysis). The LOD given by Scanelis (near to the 100% level in the conditions in which the test is performed) equals 3 times the LOD at the 95% level. Positive controls corresponding to this threshold are included in each analysis series, in order to certify the result reproducibility. For each assay this LOD is indicated on the analysis report.