title: A longitudinal evaluation of performance of automated BCR-ABL1 quantitation using cartridge-based detection system.
abstract: An automated cartridge-based detection system (GeneXpert; Cepheid) is being widely adopted in low throughput laboratories for monitoring BCR-ABL1 transcript in chronic myelogenous leukaemia. This Australian study evaluated the longitudinal performance specific characteristics of the automated system.The automated cartridge-based system was compared prospectively with the manual qRT-PCR-based reference method at SA Pathology, Adelaide, over a period of 2.5 years. A conversion factor determination was followed by four re-validations. Peripheral blood samples (n = 129) with international scale (IS) values within detectable range were selected for assessment. The mean bias, proportion of results within specified fold difference (2-, 3- and 5-fold), the concordance rate of major molecular remission (MMR) and concordance across a range of IS values on paired samples were evaluated.The initial conversion factor for the automated system was determined as 0.43. Except for the second re-validation, where a negative bias of 1.9-fold was detected, all other biases fell within desirable limits. A cartridge-specific conversion factor and efficiency value was introduced and the conversion factor was confirmed to be stable in subsequent re-validation cycles. Concordance with the reference method/laboratory at >0.1-≤10 IS was 78.2% and at ≤0.001 was 80%, compared to 86.8% in the >0.01-≤0.1 IS range. The overall and MMR concordance were 85.7% and 94% respectively, for samples that fell within ± 5-fold of the reference laboratory value over the entire period of study.Conversion factor and performance specific characteristics for the automated system were longitudinally stable in the clinically relevant range, following introduction by the manufacturer of lot specific efficiency values.
authors.affiliation: 1Haematology Department, Calvary Mater Hospital, Waratah 2Division of Haematology, Hunter Area Pathology Service/Pathology North 3School of Medicine and Public Health, Faculty of Health, University of Newcastle 4Molecular Medicine Department, Hunter Area Pathology Service/Pathology North, John Hunter Hospital, New Lambton, NSW 5SA Pathology and Centre for Cancer Biology, Adelaide 6School of Medicine, University of Adelaide, SA, Australia.
authors.forename: Anoop
authors.initials: A
authors.lastname: Enjeti
authors.forename: Neil
authors.initials: N
authors.lastname: Granter
authors.forename: Asma
authors.initials: A
authors.lastname: Ashraf
authors.forename: Linda
authors.initials: L
authors.lastname: Fletcher
authors.forename: Susan
authors.initials: S
authors.lastname: Branford
authors.forename: Philip
authors.initials: P
authors.lastname: Rowlings
authors.forename: Susan
authors.initials: S
authors.lastname: Dooley
mesh_terms: D001331:Automation; D016044:Fusion Proteins, bcr-abl / Q000097:blood*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood* / Q000235:genetics*; D008137:Longitudinal Studies; D060888:Real-Time Polymerase Chain Reaction / Q000295:instrumentation*
chemical_list: C581634:BCR-ABL1 fusion protein, human; D016044:Fusion Proteins, bcr-abl