Change in troponin concentrations in patients with macrotroponin: An in vitro mixing study
| Autor: | Leah Ha, Campbell Le Heron, Lisa Aspin, Leo Lam, Campbell Kyle |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
030213 general clinical medicine
Clinical Biochemistry Endogeny 030204 cardiovascular system & hematology Antigen-Antibody Reactions Andrology 03 medical and health sciences 0302 clinical medicine Troponin I medicine Humans In patient health care economics and organizations Autoantibodies Immunoassay biology medicine.diagnostic_test Chemistry Autoantibody General Medicine Mixing study Troponin In vitro Chromatography Gel biology.protein Reagent Kits Diagnostic |
| Zdroj: | Clinical Biochemistry. 85:43-48 |
| ISSN: | 0009-9120 |
| Popis: | Macrotroponin is a complex formed between endogenous cardiac troponin autoantibodies (cTnAABs) and circulating cardiac troponin (cTn). The potential effect of macrotroponin on current high sensitivity cTn assays has not been fully explored but has recently been identified as a major cause of discrepancy in cTn results between assays. In this study we investigated the effects of mixing troponin (cTn) standards to specimens with and without macrotroponin.Macrotroponin was identified in specimens by a recovery of cTnI 40% following protein A immunoglobulin depletion. Troponin standards containing cTn-IC and cTn-TIC complexes were mixed with serum samples, with (n = 20) and without (n = 10) the presence of macrotroponin. Specimens were tested for cTn before and after mixing by three commercially available high sensitivity cTn assays. Gel filtration chromatography was carried out on five specimens with macrotroponin and each fraction was analzyed by multiple cTn assays.Following mixing with cTn-TIC standard, all specimens with macrotroponin had a markedly reduced absolute increase in cTnI, indicating negative analytical interference due to macrotroponin. Following mixing with the cTn-IC standard, specimens with macrotroponin demonstrated highly variable changes in cTnI, suggesting significant heterogeneity in macrotroponin complex reactivity between individuals. When the ratio of change, calculated by dividing the absolute change between two cTn assays, was compared between specimens with and without macrotroponin, significant differences were observed (p 0.001). These findings were supported by variable migration of peak cTn activity on gel filtration chromatography.Macrotroponin leads to assay dependent analytical interference affecting current high sensitivity troponin I assays. Furthermore, endogenously occurring cTnAABs are conformationally specific and the analytical effects vary between assays and individuals. |
| Databáze: | OpenAIRE |
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