Although the S100B levels in CSF are forty folds higher than serum, serum S100B level has been ascertained to significantly rise following ischemic stroke from 10 hours to 2-3 days from onset of stroke.52 In addition to the increasing S100B profile, serum S100B levels are helpful in distinguishing between nonvascular vertigo and posterior circulation strokes. The gene discussed is S100B; the disease is ischemic stroke.