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Open Access Research

Comparative evaluation of the QIAsymphony RGQ system with the easyMAG/R-gene combination for the quantitation of cytomegalovirus DNA load in whole blood

Sylvie Pillet, Thomas Bourlet and Bruno Pozzetto*

Author Affiliations

Laboratory of Bacteriology-Virology-Hygiene, University Hospital of Saint-Etienne, Saint-Etienne Cedex 02, F-42055, France

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Virology Journal 2012, 9:231  doi:10.1186/1743-422X-9-231

Published: 9 October 2012

Abstract

Background

The detection of cytomegalovirus (CMV) DNA in blood is a key feature of the virological surveillance of immunocompromised patients.

Methods

The QIAsymphony RGQ system (QIAGEN S.A.S., France) combines the extraction/distribution steps on QIAsymphony SP/AS instruments with amplification on a Rotor-Gene Q RT-PCR machine. This system was compared to a strategy combining an extraction step on the NUCLISENS easyMAG platform (bioMérieux) with the CMV R-gene kit (Argene) on 100 whole blood specimens collected from immunocompromised patients of the University Hospital of Saint-Etienne, France.

Results

The overall agreement between the two strategies was 86% (kappa coefficient of 0.67); the 14 discrepant results corresponded to low DNA loads. The 62 samples found positive with both tests were correlated (Pearson r coefficient of 0.70, P < 0.01) despite an over quantitation of 0.25 log10 copies/ml with the easyMAG/Argene strategy (P < 0.001). Very close results were also obtained with a commercial panel of 10 samples with CMV loads ranging from 2.36 to 6.41 log10 copies/ml. The inter-run and intra-run variability was consistently lower with the QIAGEN platform.

Conclusions

These results validate the performance of the QIAsymphony RGQ system for the routine quantitation of CMV DNA. This fully-automated platform reduces the hands-on time and improves standardization, traceability and quality control assessment.

Keywords:
CMV; Viral load; Automation; Molecular biology; Real-time PCR