Serum S100B protein concentration in brain-dead organ donors: a pilot study.

BACKGROUND Protein S100B is considered to be a marker of brain damage, but there is a paucity of data regarding the utility of its assessment in brain-dead organ donors. The aim of the study was to compare serum protein S100B concentrations between brain-dead organ donors and patients with a confirmed permanent neurological deficit but without signs of brain death. METHODS The concentration of serum S100B protein was measured in 12 brain-dead organ donors (including 7 males with a median age of 40 years). All measurements were taken when brain death was confirmed by the commission. Twenty-nine patients (including 13 males with a median age of 63 years) who died in the medical ICU with confirmed permanent brain injury without signs of brain death acted as controls. In these patients, S-100B protein measurements were performed upon ICU admission. RESULTS In brain-dead organ donors, the median values of serum S100B protein were much higher in comparison to the control group (median and IQR, respectively: 5.04 μg L⁻¹; 1.775-6.765 vs 0.897 μg L⁻¹; 0.324-1.880, P < 0.001). S100B serum values > 1.81 μg L⁻¹ predicted brain death with the highest accuracy (AUROC = 0.83; 95% CI 0.68-0.93; P < 0.001). CONCLUSION Concentrations of serum S100B protein in brain-dead organ donors are extremely high and may support the diagnosis of brain death. This fact may be of value when the presence of reflex movements (frequently reported despite brain death) might delay determination of brain death and result in the failure of organ donation.