Serum S100B levels after meningioma surgery: A comparison of two laboratory assays.
BACKGROUND
S100B protein is a potential biomarker of central nervous system insult. This study quantitatively compared two methods for assessing serum concentration of S100B.


METHODS
A prospective, observational study performed in a single tertiary medical center. Included were fifty two consecutive adult patients undergoing surgery for meningioma that provided blood samples for determination of S100B concentrations. Eighty samples (40 pre-operative and 40 postoperative) were randomly selected for batch testing. Each sample was divided into two aliquots. These were analyzed by ELISA (Sangtec) and a commercial kit (Roche Elecsys(R)) for S100B concentrations. Statistical analysis included regression modelling and Bland-Altman analysis.


RESULTS
A parsimonious linear model best described the prediction of commercial kit values by those determined by ELISA (y = 0.045 + 0.277*x, x = ELISA value, R2 = 0.732). ELISA measurements tended to be higher than commercial kit measurements. This discrepancy increased linearly with increasing S100B concentrations. At concentrations above 0.7 microg/L the paired measurements were consistently outside the limits of agreement in the Bland-Altman display. Similar to other studies that used alternative measurement methods, sex and age related differences in serum S100B levels were not detected using the Elecsys(R) (p = 0.643 and 0.728 respectively).


CONCLUSIONS
Although a generally linear relationship exists between serum S100B concentrations measured by ELISA and a commercially available kit, ELISA values tended to be higher than commercial kit measurements particularly at concentrations over 0.7 microg/L, which are suggestive of brain injury. International standardization of commercial kits is required before the predictive validity of S100B for brain damage can be effectively assessed in clinical practice.
Einav
Sharon
S
The Intensive Care Unit of the Shaare Zedek Medical Center, affiliated with the Hebrew University, POB 3235, Jerusalem 91031, Israel.
Itshayek
Eyal
E
The Department of Neurosurgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Kark
Jeremy D
JD
The Epidemiology Unit, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Ovadia
Haim
H
The Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Weiniger
Carolyn F
CF
The Department of Anesthesia, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Shoshan
Yigal
Y
The Department of Neurosurgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel.