GDF15 and heart failure: Other key biomarkers which appeared in multiple studies were High sensitivity Troponin T (HsTnT), C-Reactive Protein (CRP), Cancer Antigen 125 (CA125), creatinine, Suppression of Tumorigenicity 2 (ST2), Galectin-3 (GAL-3) and Growth Differentiation Factor 15 (GDF-15) [22, 27, 33–35, 37, 41, 42], indicating that repeat measures of these markers are of interest within heart failure populations.