Discrepancy between Cardiac Troponin Assays Due to Endogenous Antibodies.
Clin Chem
; 66(3): 445-454, 2020 03 01.
Article
em En
| MEDLINE
| ID: mdl-32031592
ABSTRACT
BACKGROUND:
Despite well-described analytical effects of autoantibodies against cardiac troponin (cTn) I on experimental assays, no study has systematically examined their impact on cTn assays in clinical use. We determined the effects of endogenous antibodies on 5 different cTnI assays and a cTnT assay.METHODS:
cTn was measured by 6methods:
Siemens hs-cTnI Centaur, Siemens hs-cTnI Vista, Abbott hs-cTnI Architect, Beckman hs-cTnI Access, Beckman cTnI Access, and Roche hs-cTnT Elecsys. Measurements were repeated on 5 assays (all except Siemens hs-cTnI Vista) following immunoglobulin depletion by incubation with protein A. Low recovery of cTnI (<40%) following immunoglobulin depletion was considered positive for macro-cTnI. Protein A findings were validated by gel filtration chromatography and polyethylene glycol precipitation.RESULTS:
In a sample of 223 specimens selected from a community laboratory that uses the Siemens hs-cTnI Centaur assay and from which cTn was requested, 76% of samples demonstrated increased cTnI (median, 88 ng/L; interquartile range, 62-204 ng/L). Macro-cTnI was observed in 123 (55%) of the 223 specimens. Comparisons of cTnI assays markedly improved once patients with macro-cTnI were removed. Passing-Bablok regression analysis between hs-cTnI assays demonstrated different slopes for patients with and without macro-cTnI. In patients with macro-cTnI, 89 (72%) showed no effect on the recovery of cTnT, whereas 34 (28%) had reduced recovery of cTnT. The proportion of results above the manufacturers' 99th percentile varied with the cTn assay and macro-cTnI status.CONCLUSION:
We suggest that the observed discrepancy between hs-cTnI assays may be attributed in part to the presence of macro-cTnI.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Bioensaio
/
Troponina I
/
Troponina T
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article