title: Calibration of BCR-ABL1 mRNA quantification methods using genetic reference materials is a valid strategy to report results on the international scale.
abstract: OBJECTIVE
  Until recently, diagnostic laboratories that wanted to report on the international scale had limited options: they had to align their BCR-ABL1 quantification methods through a sample exchange with a reference laboratory to derive a conversion factor. However, commercial methods calibrated on the World Health Organization genetic reference panel are now available. We report results from a study designed to assess the comparability of the two alignment strategies.
  
  
  METHODS
  Sixty follow-up samples from chronic myeloid leukemia patients were included. Two commercial methods calibrated on the genetic reference panel were compared to two conversion factor methods routinely used at Saint-Louis Hospital, Paris, and at Lille University Hospital. Results were matched against concordance criteria (i.e., obtaining at least two of the three following landmarks: 50, 75 and 90% of the patient samples within a 2-fold, 3-fold and 5-fold range, respectively).
  
  
  RESULTS
  Out of the 60 samples, more than 32 were available for comparison. Compared to the conversion factor method, the two commercial methods were within a 2-fold, 3-fold and 5-fold range for 53 and 59%, 89 and 88%, 100 and 97%, respectively of the samples analyzed at Saint-Louis. At Lille, results were 45 and 85%, 76 and 97%, 100 and 100%, respectively. Agreements between methods were observed in the four comparisons performed.
  
  
  CONCLUSIONS
  Our data show that the two commercial methods selected are concordant with the conversion factor methods. This study brings the proof of principle that alignment on the international scale using the genetic reference panel is compatible with the patient sample exchange procedure. We believe that these results are particularly important for diagnostic laboratories wishing to adopt commercial methods.
authors.affiliation: Laboratory of Hematology, University Hospital Saint-Louis, AP-HP, Paris, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Mauté
authors.affiliation: Laboratory of Hematology, CHRU, Lille, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Nibourel
authors.affiliation: Department of Clinical Hematology Immunology Oncology, University Hospital Saint-Louis, AP-HP, Paris, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Réa
authors.affiliation: Department of Clinical Hematology, CHRU Lille, Lille, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Coiteux
authors.affiliation: Laboratory of Hematology, CHRU, Lille, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Grardel
authors.affiliation: Laboratory of Hematology, CHRU, Lille, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Preudhomme
authors.affiliation: Laboratory of Hematology, University Hospital Saint-Louis, AP-HP, Paris, France; EA3518, University Paris Diderot, Paris, France. Electronic address: jean-michel.cayuela@sls.aphp.fr.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Cayuela
mesh_terms: D002138:Calibration; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D012015:Reference Standards
chemical_list: C581634:BCR-ABL1 fusion protein, human; D012333:RNA, Messenger; D016044:Fusion Proteins, bcr-abl
keywords: BCR–ABL1; Chronic myeloid leukemia; International scale; Real-time quantitative PCR; Standardization