Troponin-specific autoantibody interference in different cardiac troponin I assay configurations
| Autor: | Tanja Savukoski, Noora Ristiniemi, Bertil Lindahl, Janne Engblom, Kim Pettersson, Kai M. Eggers, Emilia Engström, Saara Wittfooth, Per Venge |
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| Rok vydání: | 2012 |
| Předmět: |
Clinical Biochemistry
macromolecular substances Pharmacology Sensitivity and Specificity Epitope Coronary artery disease Epitopes Troponin complex Troponin I medicine Humans Multicenter Studies as Topic False Positive Reactions Prospective Studies Acute Coronary Syndrome False Negative Reactions Autoantibodies Immunoassay Chromatography biology medicine.diagnostic_test Chemistry Biochemistry (medical) Autoantibody medicine.disease Troponin cardiovascular system biology.protein Antibody |
| Zdroj: | Clinical chemistry. 58(6) |
| ISSN: | 1530-8561 |
| Popis: | BACKGROUNDAutoantibodies to cardiac troponins (cTnAAb) can interfere with the measurement of cardiac troponin I (cTnI) by immunoassays. The aim of this study was to explore the degree of cTnAAb interference in different cTnI assay configurations.METHODSTernary troponin complex was added into samples (serum or plasma, n = 132, 68% cTnAAb positive) from individuals without known cardiac conditions. The recovery of cTnI was then measured with 6 investigational cTnI assays (2, 3, or 4 antibodies per assay). Three of these assays were then selected for further comparison by use of samples (plasma, n = 210, 33% cTnAAb positive) from non–ST-elevation acute coronary syndrome patients in the FRISC-II (FRagmin/Fast Revascularisation during InStability in Coronary artery disease) cohort. Finally, these results were compared to those obtained with 3 commercial cTnI assays.RESULTSAnalytical recoveries varied widely among the 6 investigational assays. Notably the low recoveries (median 9%) of the midfragment-targeting reference assay were normalized (median 103%) with the use of the 4-antibody assay construct (3 capture, 1 tracer antibody) with only 1 antibody against a midfragment epitope. Reduced analytical recoveries correlated closely with measured autoantibody amounts. cTnI concentrations from cTnAAb-positive patient samples determined with 3 investigational assays confirmed the reduced concentrations expected from the low analytical recoveries. The results from the commercial cTnI assays with antibody selections representative for contemporary assay constructs revealed a similar underestimation (up to 20-fold) of cTnI in cTnAAb-positive samples.CONCLUSIONSA novel cTnI assay deviating from the conventional IFCC-recommended midfragment approach substantially improves cTnI detection in samples containing cTnAAbs. |
| Databáze: | OpenAIRE |
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