Rapid measurement of S-100B serum protein levels by Elecsys S100 immunoassay in patients undergoing carotid artery stenting or endarterectomy

Objectives: This study was designed to apply the rapid Elecsys® S100 immunoassay for real-time measurement of S100 protein serum levels indicating acute brain damage in patients undergoing carotid artery stenting (CAS) or endarterectomy (CEA). Design and Methods: Data of 14 CAS patients were compared to those of 43 CEA and 14 control patients undergoing coronary angiography (CA). S100 serum levels were measured by the full-automatic Elecsys® S100 immunoassay and compared to those obtained by the well-established LIA-mat® S100 system. Results: In contrast to CAS and CA patients, median S100 serum levels of CEA patients significantly increased to 0.24 ng/mL before declamping, but subsequently returned to baseline. Three CEA patients with neurological deficits showed sustained elevated S100 levels 6 h after extubation. Absolute S100 values were not significantly different between the two methods. Bland-Altman plot analyses displayed a good agreement, mostly indicating slightly smaller values applying the Elecsys® S100 system. Conclusions: The Elecsys® S100 system appears to be suitable for rapid real-time detection of neurological deficits in patients undergoing CAS and CEA. Persistent elevations of Elecsys® S100 levels during CEA were associated with prolonged neurological disorders, whereas transient increases seem to represent impaired blood-brain barrier integrity without neurological deficits.