S100B and Stroke: A 12-hours serum S100B level more than 0.35 ug/l could predict the malignant infarction with good sensitivity and specificity (75% and 80%, respectively) while a 24-hours serum S100B level more than 1.03 ug/l could predict the event with higher sensitivity and specificity (94% and 83%, respectively).57 Several studies have shown that serum S100B levels measured in samples taken more than 24 h after stroke onset had a strong correlation with the degree of neurological deficit and the final infarct volume.