title: A new highly automated extraction system for quantitative real-time PCRs from whole blood samples: routine monitoring of opportunistic infections in immunosuppressed patients.
abstract: BACKGROUND
  Rapid, high throughput extraction systems are needed to monitor viral infections in immunosuppressed patients.
  
  
  OBJECTIVE
  Evaluate the performance of the MagNA Pure 96™ extraction system, and compare it to the COBAS Ampliprep™ for quantitative real-time PCR from whole blood samples.
  
  
  METHODS
  Compare the MagNA Pure LC™, COBAS Ampliprep™ and MagNA Pure 96™ using ten-fold dilutions of blood samples containing cytomegalovirus. Evaluate analytical performances of the MagNA Pure 96™ from test samples containing cytomegalovirus. Evaluate clinical performances from 209 blood samples collected prospectively, extracted with the COBAS Ampliprep™ and the MagNA Pure 96™ systems and tested for cytomegalovirus, Epstein-Barr, BK and JC viruses.
  
  
  RESULTS
  All three extraction systems gave similar results with dilutions of a cytomegalovirus-positive sample. Analytical tests showed that the limit of detection was 500 copies/ml, specificity was 100%, with no cross-contamination. Quantification was linear from 3.0 to 6.0 log(10)copies/ml. Intra-assay variation was 8.3-0.9% and inter-assay variation 8.8-5.2%. Clinical specimens extracted with the MagNA Pure 96™ and COBAS Ampliprep™ instruments agreed well for cytomegalovirus (r=0.54; p=0.07), Epstein-Barr virus (0.69; p=0.0005) and BK virus (0.85; p=0.01). All 55 samples were negative for JC virus. Mean loads were similar for cytomegalovirus (0.17 log(10)copies/ml) and BK virus (-0.24 log(10)copies/ml) while that of Epstein-Barr virus was slightly lower (1.02 log(10)copies/ml).
  
  
  CONCLUSIONS
  The MagNA Pure 96™ instrument is an easy-to-use, reliable high throughput platform for extracting nucleic acid from clinical whole blood specimens.
authors.affiliation: Department of Virology, CH Toulouse, France. mengelle.c@chu-toulouse.fr
authors.forename: C
authors.initials: C
authors.lastname: Mengelle
authors.forename: J-M
authors.initials: JM
authors.lastname: Mansuy
authors.forename: K
authors.initials: K
authors.lastname: Sauné
authors.forename: C
authors.initials: C
authors.lastname: Barthe
authors.forename: J
authors.initials: J
authors.lastname: Boineau
authors.forename: J
authors.initials: J
authors.lastname: Izopet
mesh_terms: D001331:Automation / Q000379:methods*; D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification; D003586:Cytomegalovirus Infections / Q000097:blood / Q000821:virology; D004266:DNA Virus Infections / Q000097:blood / Q000821:virology; D004267:DNA Viruses / Q000235:genetics / Q000302:isolation & purification*; D004279:DNA, Viral / Q000097:blood / Q000302:isolation & purification*; D006801:Humans; D016867:Immunocompromised Host; D009894:Opportunistic Infections / Q000097:blood* / Q000821:virology; D011933:Reagent Kits, Diagnostic; D060888:Real-Time Polymerase Chain Reaction / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019562:Viral Load / Q000379:methods
chemical_list: D004279:DNA, Viral; D011933:Reagent Kits, Diagnostic