Low prevalence of detectable serum cardiac troponin I among healthy Tanzanian adults: observational study

Background: Cardiac troponin test is used in detecting various heart disorders. The objective of this study was to establish normal reference levels for serum cardiac Troponin I which could be utilized for selection of vaccines and determine any electrocardiogram (EKG) changes among healthy volunteers.
Methods: A total of 263 healthy blood donors from Dar es Salaam, Tanzania were included in this substudy. A thorough medical history and physical examination to rule out any major chronic disease like heart failure, chronic kidney diseases, diabetes mellitus and HIV was undertaken. Ten mL of blood sample for the purpose of establishing normal reference values for Troponin I assessment and parallel EKG was performed to all participants.
Results: Of the 263 subjects, males were156 (59.3%) and females were 107 (40.7%). Median (range) age was 34 years old. The manufacture’s reference level for serum Cardiac Troponin I was 0.00-0.39 μg/L. Serum Cardiac Troponin I was detected in two blood donors (0.76%). However, their Troponin I levels were within the manufacturer’s normal range (0.01-0.36 μg/L). Clinically both subjects were healthy and their EKG tracing were unremarkable.
Conclusions: Our study has shown that among healthy subjects, detectable serum cardiac Troponin I is a rare finding. The manufacturer’s range is applicable in our setting and can be used in the ongoing vaccine trial. The significance of minimally elevated serum cardiac Troponin I may represent a subclinical cardiac injury and have important clinical implications, a hypothesis that should be tested in future longitudinal outcome studies.

Keywords
cardiac Troponin I; electrocardiogram; blood donors; vaccine trial; Tanzania