Growth differentiation factor 15 (GDF-15) has been suggested as a prognostic
biomarker for
bleeding and mortality in
atrial fibrillation (AF). To date, serum and
EDTA matrices are standardized for the
GDF-15 assay but it is unclear if it can be measured also in
citrate. In this study, we aim to investigate if the Elecsys
GDF-15 assay (Roche Diagnostics, Mannheim, Germany) can be determined accurately in
citrate samples in a cohort of 10 patients with AF and 10 healthy controls. From January 2018 to March 2018, we included healthy controls and patients with AF under
vitamin K antagonists in a tertiary hospital. Blood samples were drawn in both groups. We included 10 controls (50% males, mean age 36.4±8.9 years) and 10 patients with AF (80% males, mean age 76.5±16.6 years). The mean
GDF-15 levels were increased in patients with AF in comparison to healthy controls, as expected by the presence of a heart-related condition and the higher age of this population. In healthy controls,
GDF-15 levels showed an optimal correlation between
EDTA-serum (r=0.975; p<0.001),
EDTA-
citrate (r=0.972; p<0.001), and serum-
citrate (r=0.997; p<0.001) samples. This was also observed in patients with AF:
EDTA-serum (r=0.975; p<0.001), serum-
citrate (r=0.835; p=0.003), and
EDTA-
citrate (r=0.768; p=0.009). Our results demonstrate that
citrate samples may be used for the determination of
GDF-15 in AF given the positive and good correlation with
EDTA and serum matrices. Further studies should validate these observations.