S-100 protein and neuron-specific enolase concentrations in blood as indicators of infarction volume and prognosis in acute ischemic stroke

Background and Purpose Better techniques are needed to monitor infarction volume and predict neurological outcome after ischemic brain infarction. We evaluated the usefulness of serial measurements of S-100 protein versus neuron-specific enolase (NSE) in blood samples from patients with acute stroke. Methods Using nonisotopic sandwich immunoassays, we measured plasma concentrations of S-100 protein and NSE on admission and on days 3, 4, 7, and 14 after infarction in 44 patients (age range, 22 to 86 years; mean age, 65.1 years; 12 female, 32 male). Infarct volume was measured by volumetric CT on day 4 after ictus, and clinical outcome was assessed at discharge from hospital with the Activities of Daily Living Scale and 6 months after infarction with the Glasgow Outcome Scale. Results Peak blood levels of S-100 protein were found on day 2.5+/-1.3, and peak levels of NSE were found on day 1.9+/-0.8 after infarction. Peak plasma levels of S-100 protein correlated well with infarct volume (r=.75, P<.001) and with clinical outcome assessed with the Glasgow Outcome Scale (r=.51, P<.001). Serum levels of NSE correlated with infarct volume (r=.37, P<.05) but not with clinical outcome (r=.18, P>.05). Conclusions The results of our study indicate that measuring blood concentrations of S-100 protein periodically in the first 10 days after cerebral infarction helps to predict infarct volume and the long-term neurological outcome more accurately than periodic measurements of blood concentrations of NSE.