Urs Wilgen1, Carel J Pretorius2, Michael J Gould3, Jacobus Pj Ungerer4. 1. Department of Chemical Pathology, Pathology Queensland, The Royal Brisbane Women's and Children's Hospital, Herston, Queensland, Australia School of Medicine, University of Queensland, Brisbane, St Lucia, Queensland, Australia Urs.Wilgen@health.qld.gov.au. 2. Department of Chemical Pathology, Pathology Queensland, The Royal Brisbane Women's and Children's Hospital, Herston, Queensland, Australia School of Medicine, University of Queensland, Brisbane, St Lucia, Queensland, Australia. 3. Department of Chemical Pathology, Pathology Queensland, The Prince Charles Hospital, Chermside, Queensland, Australia. 4. Department of Chemical Pathology, Pathology Queensland, The Royal Brisbane Women's and Children's Hospital, Herston, Queensland, Australia.
Abstract
BACKGROUND: False-positive cardiac troponin I results as a result of carryover have previously been reported on the Beckman Coulter AccuTnI assay. We sought to determine if the carryover problem had been resolved with the new AccuTnI + 3 assay. METHODS: Carryover experiments were performed in parallel on the Beckman Coulter Access2 analyser using the legacy AccuTnI and new AccuTnI + 3 assays. The same negative patient pool sample was analysed before and after a single analysis of an extremely elevated patient sample. RESULTS: Analysis of a single extremely high sample caused elevations above the 99th percentile cut-off, and thus false-positive cardiac troponin I results on both assays. Both assays demonstrated carryover and subsequent further elevations in negative pool results the following day. CONCLUSIONS: Our study replicates our previously published findings of carryover and reagent pack contamination on the AccuTnI assay. Despite improvements on the new AccuTnI + 3 assay, carryover and reagent pack contamination are still present.
BACKGROUND: False-positive cardiac troponin I results as a result of carryover have previously been reported on the Beckman Coulter AccuTnI assay. We sought to determine if the carryover problem had been resolved with the new AccuTnI + 3 assay. METHODS: Carryover experiments were performed in parallel on the Beckman Coulter Access2 analyser using the legacy AccuTnI and new AccuTnI + 3 assays. The same negative patient pool sample was analysed before and after a single analysis of an extremely elevated patient sample. RESULTS: Analysis of a single extremely high sample caused elevations above the 99th percentile cut-off, and thus false-positive cardiac troponin I results on both assays. Both assays demonstrated carryover and subsequent further elevations in negative pool results the following day. CONCLUSIONS: Our study replicates our previously published findings of carryover and reagent pack contamination on the AccuTnI assay. Despite improvements on the new AccuTnI + 3 assay, carryover and reagent pack contamination are still present.