Evaluation of an automated sample preparation system (MDx) in combination with affigene CMV trender

Abstract number: 1733_1228

Abbate I., Finnstrom N., Garbuglia A., Solmone M., Selvaggini S., Bennici E., Neri S., Brega C., Capobianchi M.

Background: Monitoring of Cytomegalovirus (CMV) viral load is efficiently performed by using molecular diagnostics based on PCR, such as the CE-labelled affigene CMV trender assay (Sangtec, Bromma, Sweden). Today, a number of automated nucleic acid sample preparation systems are available for a high throughput laboratory. One of them is the BioRobot MDx Workstation (MDx) from Qiagen (Hilden, Germany).

This study aims to evaluate the MDx in combination with the PCR system affigene CMV trender. Moreover, on a small number of clinical samples a comparative analysis was conducted between affigene CMV trender assay and an house nested PCR method.

Materials and Methods: For the evaluation, the 2005 QCMD panel for CMV was used. To mimic the laboratory routine for analysing whole blood patient sample, freeze-dried samples from the QCMD panel were diluted into whole blood, or in water and diluted in the lysis buffer of the extraction kit. Each of the panel member was extracted twice on the MDx and thereafter each extraction was amplified in duplicates using affigene CMV trender.

Fiftyfour clinical whole blood samples were also included in the study. Extraction was performed as above and the amplification was done in parallel with affigene CMV trender assay and with nested PCR.

Results: The average results from each of the QCMD samples showed a less than 0.25 log difference compared to the average reported value in the QCMD report based on 30 different datasets. One sample varied more than 0.25 log compared to the reported values. However, this sample was in the area of the limit of detection for the assay. The negative sample was reported negative in all four replicates. The comparison between affigene CMV trender assay and nested PCR showed a good concordance. Only 3 out of 54 patients showed discordant results, being 2 of them CMV DNA positive only in nested PCR and 1 positive only when using CMV trender. Moreover, the affigene CMV trender assay was able to quantify the CMV DNA present in the positive samples with a mean value of 43750 ± 26265 CMV DNA copies/mL.

Conclusions: The BioRobot MDx Workstation works well in combination with the affigene CMV trender PCR assay as verified on both QCMD panel and clinical samples. This opens up the possibilities for quicker and accurate CMV monitoring for high-throughout laboratories.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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