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Updated: May 13, 2026

A Duplex Digital PCR Assay for Simultaneous Quantification of the Enterococcus spp. and the Human Fecal-associated HF183 Marker in Waters
Published on: March 9, 2016
The characterization and certification of a quantitative reference material for Legionella detection and
M Baume1, L Garrelly, J P Facon
1Hospices Civils de Lyon, Centre National de Référence des Légionelles, Lyon, France.
Aims:
The characterization and certification of a Legionella DNA quantitative reference material as a primary measurement standard for Legionella qPCR.
Methods And Results:
Twelve laboratories participated in a collaborative certification campaign. A candidate reference DNA material was analysed through PCR-based limiting dilution assays (LDAs). The validated data were used to statistically assign both a reference value and an associated uncertainty to the reference material.
Conclusions:
This LDA method allowed for the direct quantification of the amount of Legionella DNA per tube in genomic units (GU) and the determination of the associated uncertainties. This method could be used for the certification of all types of microbiological standards for qPCR.
Significance And Impact Of The Study:
The use of this primary standard will improve the accuracy of Legionella qPCR measurements and the overall consistency of these measurements among different laboratories. The extensive use of this certified reference material (CRM) has been integrated in the French standard NF T90-471 (April 2010) and in the ISO Technical Specification 12 869 (Anon 2012 International Standardisation Organisation) for validating qPCR methods and ensuring the reliability of these methods.

