Cardiac Troponin I carryover by very high patient samples still causes false-positive results on the Beckman Coulter AccuTnI + 3.
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.
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.
Urs
U
Wilgen
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.
Carel J
CJ
Pretorius
Department of Chemical Pathology, Pathology Queensland, The Prince Charles Hospital, Chermside, Queensland, Australia.
Michael J
MJ
Gould
Department of Chemical Pathology, Pathology Queensland, The Royal Brisbane Women's and Children's Hospital, Herston, Queensland, Australia.
Jacobus Pj
JP
Ungerer
D016477:Artifacts; D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000592:standards; D005189:False Positive Reactions; D006801:Humans; D009206:Myocardium / Q000378:metabolism*; D012015:Reference Standards; D019210:Troponin I / Q000097:blood*
D019210:Troponin I
Troponin; analytical systems; immunoassay