Unexpected high troponin T and I values in a child with hypertrophic cardiomyopathy and acute chest pain: a case report

Abstract

Background Elevated troponin T and/or troponin I can be ascribed to multiple causes, mostly resulting from cardiac tissue damage and in lesser numbers resulting from non-cardiac related causes. The presence of macrotroponins is easily overlooked with potentially negative consequences. Case Summary This case report presents a case study of a 12 year old child known to have a MYH7-gene associated hypertrophic cardiomyopathy with acute chest pain combined with an unexpected high troponin T and I. A cardiac cause was deemed unlikely after additional investigation, as these showed no abnormalities. After consulting the laboratory specialist it could be concluded that the high troponin T and I were a result of macrotroponin complexes, a protein complex consisting of circulating protein and endogenous autoantibodies against that protein, resulting in elevated values with misguiding and uncertain clinical significance. Discussion Awareness of the existence of macrotroponins could have prevented costly diagnostics and prolonged hospital admission with grave psychological impact, especially in children.

Role of Antitroponin Antibodies and Macrotroponin in the Clinical Interpretation of Cardiac Troponin

“… 12 , 52 However, interference related to macrotroponin T may be encountered in routine clinical practice (Figure S4 ), and macrotroponins involving both cTn (I and T) are also reported. 52 , 53 The troponins have a normal half‐life in plasma of around 120 minutes; while in the presence of macrotroponin, troponins are maintained in the circulation for days or longer with an increased absolute concentration (Figures S5 through S7 ). 27 Indeed, the results of cTn assays may be increased and stable for years with macrotroponin (Figure S7 ), but the extended kinetics and accumulation of cTn are primarily related to the detection of macrotroponin by the assay and not to persistent significant cTn release (Figure 4 ).…”